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Eating Fried Potatoes Linked to Higher Risk of Death, Study Says

How your spuds are cooked is key to your health. People who eat fried potatoes two or more times a week double their risk of an early death compared to those who avoid them, a recent study published in the American Journal of Clinical Nutrition found.

Eating potatoes that have not been fried was not linked to a similar early mortality risk, the researchers noted.

“Fried potatoes consumption is increasing worldwide,” warned Dr. Nicola Veronese, lead author of the study and a scientist at the National Research Council in Padova, Italy.

In 2014, Americans consumed 112.1 pounds of potatoes per person, according to the National Potato Council. Of that total, 33.5 pounds were fresh potatoes, the remaining 78.5 pounds were processed. According to the US Department of Agriculture, the majority of processed potatoes North Americans eat are French fries.

Trans fats in fried potatoes

Veronese and his colleagues have been tracking 4,440 people aged 45 to 79 over a period of eight years to study osteoarthritis. This research team decided to momentarily set aside the main issue of osteoarthritis and look at participants’ consumption of potatoes.

Even though most of us may have assumed that fried potatoes could be unhealthy for us, there is “very limited” scientific data on this issue, Veronese explained in an email.

So the researchers divided study participants into subgroups based on how frequently they ate potatoes each week. Over the eight years, a total of 236 of the participants died. Analyzing the data for each group, Veronese and his team found that those who ate fried potatoes two to three times each week doubled their chance of dying early compared to those who ate no fried potatoes.

French fries, potato chips, hash browns – and any other preparation requiring a fryer – are all included under the umbrella of “fried potatoes,” Veronese explained.

Age or sex of participants did not influence the result, but the data showed men were more likely than women and younger participants were more likely than older participants to enjoy the fried food.

The study is observational, meaning the researchers simply tracked the behavior of a group of people and found an association between one behavior – eating fried potatoes – and another factor – early death. Because it is an observational study, Veronese and his co-authors note it cannot be said that eating fried potatoes directly causes an early mortality – it would require more research to draw such a firm conclusion.

“Even if it is an observational study, we believe that the cooking oil, rich in trans-fat, is an important factor in explaining mortality in those eating more potatoes,” said Veronese. Trans fat has been shown to raise the “bad,” or LDL, cholesterol in the blood, which can lead to cardiovascular disease.

 

Yet, he also added that “other important factors,” including obesity, a sedentary lifestyle and use of high quantities of salt might also play a role in the early death of those eating two or more portions of fried potatoes each week.

National Potato Council CEO John Keeling said the “study isn’t relevant to the general population” since the data was collected for an osteoarthritis study and includes only patients with arthritis. “Potatoes are inherently a very healthy vegetable,” said Keeling in an email. He said a medium-sized potato is 110 calories, has no fat, no sodium, no cholesterol, and provides nearly a third of the daily vitamin C requirement with more potassium than a banana.

“How the potato is prepared will impact the calorie, fat and sodium content,” said Keeling, however the basic nutrients remain “no matter how it is prepared.”

Based on the data in the study, Keeling said, “it is very much a stretch to brand fried potatoes, or any other form of potato, as unhealthy.”

Susanna Larsson, an associate professor at the Institute of Environmental Medicine, Karolinska Institutet in Stockholm, Sweden, noted that the new study provides “no evidence” that potato consumption in and of itself may increase the risk of an early death. Larsson was not involved in the new study. Instead, it may be the “other factors” suggested by Veronese himself.

“Fried potato consumption may be an indicator of a less healthy (Western) dietary pattern which is associated with increased mortality,” said Larsson, who also conducted a study of potato consumption. Her study did not find an increased risk of cardiovascular disease linked to eating potatoes.

Understanding acrylamide

The potential danger when eating fried starchy foods, such as French fries, is acrylamide, said Stephanie Schiff, a registered dietitian at Northwell Health’s Huntington Hospital in Huntington, New York. Schiff was not involved in the study.

Acrylamide is “a chemical produced when starchy foods such as potatoes are fried, roasted or baked at a high temperature,” explained Schiff in an email. The browning process is actually a reaction that produces this chemical one shown to cause cancer in laboratory animals and considered toxic to humans, said Schiff. Acrylamide is also a potential cause of cancer, she said.

“You can reduce your intake of acrylamide by boiling or steaming starchy foods, rather than frying them,” said Schiff. “If you do fry foods, do it quickly.”

She also suggested you “go lighter” since “the darker the food, the more acrylamide it may contain.”

Finally, Schiff said that potatoes should not be stored in the refrigerator because this could lead to producing more acrylamide when the potatoes are later cooked.

“Increase your intake of fruits and vegetables for a healthier alternative,” said Schiff.

Veronese said he hopes his new study will suggest to everyone that consuming fried potatoes “could be an important risk factor for mortality. Thus, their consumption should be strongly limited.”

By Susan Scutti, CNN    Thu June 15, 2017
source: CNN


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The Healthiest Way to Cook Mushrooms Is Totally Surprising

Scientists have revealed the best way to cook mushrooms — and it’s not in a frying pan.
Mushrooms are healthy because of the significant amount of dietary fiber, protein, amino acids, vitamins (including B1, B2, B12, C, D and E) and trace minerals that they contain, as well as the fact that they’re low in fat and calories.

But, according to researchers from the Mushroom Technological Research Center of La Rioja in Spain, mushrooms’ composition, antioxidant capacity and nutritional content can be negatively affected by the cooking process.

For the study, which was published in the International Journal of Food Sciences, the team evaluated the influence of boiling, microwaving, grilling and frying white button, shiitake, oyster and king oyster mushrooms. After cooking the four types of mushrooms, which were chosen because they are the most widely consumed species of mushroom worldwide, the samples were freeze-dried and analyzed, with the results compared to raw versions.

The researchers concluded that the best way to cook mushrooms while still preserving their nutritional properties is to grill or microwave them, as the fried and boiled mushrooms showed significantly less antioxidant activity. The fried mushrooms in particular revealed a severe loss in protein and carbohydrate content, but an increase in fat.”Frying and boiling treatments produced more severe losses in proteins and antioxidants compounds, probably due to the leaching of soluble substances in the water or in the oil, which may significantly influence the nutritional value of the final product,” said Irene Roncero, one of the study’s authors, in a statement.

Kate Samuelson     May 22, 2017     TIME Health
 
source: time.com


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Still Cooking with Aluminum Foil? You’ll Want to Read This

Cooking and baking with aluminum foil is fast and convenient, and makes cleanup a cinch, but it’s not without health risks.

A lot has changed since aluminum arrived on the scene back in 1910, after the first aluminum foil rolling plant, Dr. Lauber, Neher & Cie, opened in Emmishofen, Switzerland. The first use of foil in the United States came about in 1913, when it was used to wrap Life Savers, candy bars, and gum. Eventually, aluminum foil made its way into American kitchens as a way to bake fish or roast vegetables on the barbecue, to line baking pans, and to trap steam when cooking.

And we’re using tons of it—so much that experts are getting concerned. Because according to research, some of the foil used in cooking, baking, and grilling leaches into your food, which can pose health problems over time.

According to the World Health Organization, human bodies are capable of properly releasing small amounts of aluminum efficiently, so it’s considered safe to ingest 40mg per kilogram of body weight of aluminum per day. Unfortunately, most people are ingesting far more than this.

Scientists have been looking at the potential threat that overexposure to aluminum may have on human health for years, and have found some disturbing results. For example, researchers have found high concentrations of aluminum in the brain tissue of patients with Alzheimer’s disease. Studies have also found that high aluminum intake may be linked to a reduction in the growth rate of human cells, and may be potentially harmful for patients with bone diseases or renal impairment.

A 2012 study published in the International Journal of Electrochemical Science investigated the amount of aluminum that leaches into food cooked with foil. The amount varied based on factors such as temperature and acidity (fish and tomatoes are highly acidic), but the findings showed conclusively that aluminum foil does leach into food cooked in foil. “Aluminum foil used in cooking provides an easy channel for the metal to enter the human body,” the study authors wrote. “The increase in cooking temperature causes more leaching. The leaching is also highly dependent on the pH value of the food solution, salt, and spices added to the food solutions.”

Ghada Bassioni, Associate Professor and Head of the Chemistry Division at Ain Shams University, conducted research with a group of colleagues that explored the use of aluminum for cooking and preparing food particularly at high temperatures. “The acidity of the food would enhance further leaching of aluminum into the meal,” she said, adding: “How aluminum will actually harm your body depends on many factors like your overall well-being and consequently how much your body can handle accumulation of it in relation to the allowable dosages set by the World Health Organization.”

So should you stop cooking with aluminum foil? It seems the general consensus is that we should, at the very least, cut way back.

For grilling veggies, you can get a stainless steel grilling basket, or even reusable skewers. Use a glass pan when roasting veggies in the oven; use a stainless steel cookie sheet under baking potatoes as opposed to aluminum foil to catch the mess; and even try replacing foil with banana leaves when wrapping foods for baking!

BY ALEXA ERICKSON
 
source: www.rd.com


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Microwaving food in plastic: Dangerous or not?

Let’s cover the original misinformation first: The earliest missives warned that microwaved plastic releases cancer-causing chemicals called dioxins into food. The problem with that warning is that plastics don’t contain dioxins. They are created when garbage, plastics, metals, wood, and other materials are burned. As long as you don’t burn your food in a microwave, you aren’t exposing yourself to dioxins.

Migrating chemicals

There’s no single substance called “plastic.” That term covers many materials made from an array of organic and inorganic compounds. Substances are often added to plastic to help shape or stabilize it. Two of these plasticizers are

  • bisphenol-A (BPA), added to make clear, hard plastic
  • phthalates, added to make plastic soft and flexible

BPA and phthalates are believed to be “endocrine disrupters.” These are substances that mimic human hormones, and not for the good.

When food is wrapped in plastic or placed in a plastic container and microwaved, BPA and phthalates may leak into the food. Any migration is likely to be greater with fatty foods such as meats and cheeses than with other foods.

The FDA long ago recognized the potential for small amounts of plasticizers to migrate into food. So it closely regulates plastic containers and materials that come into contact with food. The FDA requires manufacturers to test these containers using tests that meet FDA standards and specifications. It then reviews test data before approving a container for microwave use.

Some of these tests measure the migration of chemicals at temperatures that the container or wrap is likely to encounter during ordinary use. For microwave approval, the agency estimates the ratio of plastic surface area to food, how long the container is likely to be in the microwave, how often a person is likely to eat from the container, and how hot the food can be expected to get during microwaving. The scientists also measure the chemicals that leach into food and the extent to which they migrate in different kinds of foods. The maximum allowable amount is 100–1,000 times less per pound of body weight than the amount shown to harm laboratory animals over a lifetime of use. Only containers that pass this test can display a microwave-safe icon, the words “microwave safe,” or words to the effect that they’re approved for use in microwave ovens.

When Good Housekeeping microwaved food in 31 plastic containers, lids, and wraps, it found that almost none of the food contained plastic additives.

What about containers without a microwave-safe label? They aren’t necessarily unsafe; the FDA simply hasn’t determined whether it is or not.

man-microwave-dinner-into-mic

Is Styrofoam microwave safe?

Contrary to popular belief, some Styrofoam and other polystyrene containers can safely be used in the microwave. Just follow the same rule you follow for other plastic containers: Check the label.

The bottom line

Here are some things to keep in mind when using the microwave:

  • If you’re concerned about plastic wraps or containers in the microwave, transfer food to glass or ceramic containers labeled for use in microwave ovens.
  • Don’t let plastic wrap touch food during microwaving because it may melt. Wax paper, kitchen parchment paper, white paper towels, or a domed container that fits over a plate or bowl are better alternatives.
  • Most takeout containers, water bottles, and plastic tubs or jars made to hold margarine, yogurt, whipped topping, and foods such as cream cheese, mayonnaise, and mustard are not microwave-safe.
  • Microwavable takeout dinner trays are formulated for one-time use only and will say so on the package.
  • Old, scratched, or cracked containers, or those that have been microwaved many times, may leach out more plasticizers.
  • Don’t microwave plastic storage bags or plastic bags from the grocery store.
  • Before microwaving food, be sure to vent the container: leave the lid ajar, or lift the edge of the cover.

 Read more about the BPA controversy and get tips to decrease your exposure.

 Updated: October 27, 2015   Originally published: February 2006


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How to Cook Your Foods to Get the Most Nutrients Out of Them

By Franziska Spritzler / Authority Nutrition      February 17, 2016

Eating nutritious foods can improve your health and energy levels.

Surprisingly, the way you cook your food has a major effect on the amount of nutrients in it.

This article will explore how the different cooking methods affect the nutrient content of foods.

Nutrient Content is Often Altered During Cooking

Cooking food improves digestion and increases absorption of many nutrients.

For example, protein in cooked eggs is 180% more digestible than in raw eggs.

However, several key nutrients are reduced with some cooking methods.

Nutrients That May Decrease

The following nutrients are often reduced during cooking:

  • Water-soluble vitamins: vitamin C and the B vitamins — thiamin (B1), riboflavin (B2), niacin (B3), pantothenic acid (B5), pyridoxine (B6), folic acid (B7) and cobalamin (B8).
  • Fat-soluble vitamins: vitamins A, D, E and K.
  • Minerals: primarily potassium, magnesium, sodium and calcium

Bottom Line: Although cooking improves digestion and the absorption of many nutrients, the levels of some vitamins and minerals may decrease.

Boiling, Simmering and Poaching

Boiling, simmering and poaching are similar methods of water-based cooking.

These techniques differ by water temperature:

  • Poaching: less than 180°F/82°C.
  • Simmering: 185-200°F/85-93°C.
  • Boiling: 212°F/100°C.

Vegetables are generally a great source of vitamin C, but a large amount of it is lost when cooked in water.

In fact, boiling reduces vitamin C more than any other cooking method. Broccoli, spinach and lettuce may lose up to 50% or more of their vitamin C when boiled.

Because vitamin C is water-soluble and sensitive to heat, it can leach out of vegetables when they’re immersed in hot water.

B vitamins are similarly heat sensitive. Up to 60% of thiamin, niacin and other B vitamins may be lost when meat is simmered and its juices run off.

However, when the liquid containing these juices is consumed, 100% of the minerals and 70-90% of B vitamins are retained.

On the other hand, boiling fish was shown to preserve omega-3 fatty acid content significantly more than frying or microwaving.

Bottom Line: While water-based cooking methods cause the greatest losses of water-soluble vitamins, they have very little effect on omega-3 fats.

Grilling and Broiling

Grilling and broiling are similar methods of cooking with dry heat.

When grilling, the heat source comes from below, but when broiling, it comes from above.

Grilling is one of the most popular cooking methods because of the great flavor it gives food.

However, up to 40% of B vitamins and minerals may be lost during grilling or broiling when the nutrient-rich juice drips from the meat.

There are also concerns about polycyclic aromatic hydrocarbons (PAHs), which are potentially cancer-causing substances that form when meat is grilled and fat drips onto a hot surface.

Luckily, researchers have found that PAHs can be decreased by 41-89% if drippings are removed and smoke is minimized.

Bottom Line: Grilling and broiling provide great flavor but also reduce B vitamins. Grilling generates potentially cancer-causing substances.

Microwaving

Microwaving is an easy, convenient and safe method of cooking.

Short cooking times and reduced exposure to heat preserve the nutrients in microwaved food (9, 10).

Studies have found that microwaving is the best method for retaining the antioxidant activity in garlic and mushrooms.

About 20-30% of vitamin C in green vegetables is lost during microwaving, which is less than most cooking methods.

Bottom Line: Microwaving is a safe cooking method that preserves most nutrients due to short cooking times.

Roasting and Baking

Roasting and baking refer to cooking food in an oven with dry heat.

Although these terms are somewhat interchangeable, the term “roasting” is typically used for meat while “baking” is used for bread, muffins, cake and similar foods.

Most vitamin losses are minimal with this cooking method, including vitamin C.

However, due to long cooking times at high temperatures, B vitamins in roasted meat may decline by as much as 40%.

Bottom Line: Roasting or baking does not have a significant effect on most vitamins and minerals, with the exception of B vitamins.

stirfry

Sautéing and Stir-Frying

With sautéing and stir-frying, food is cooked in a saucepan over medium to high heat in a small amount of oil or butter.

These techniques are very similar, but with stir-frying the food is stirred often, the temperature is higher and the cooking time is shorter.

In general, this is a healthy way to prepare food.

Cooking for a short time without water prevents loss of B vitamins, and the addition of fat improves the absorption of plant compounds and antioxidants.

One study found that absorption of beta-carotene was 6.5 times greater in stir-friedcarrots than in raw.

In another study, blood lycopene levels increased 80% more when people consumedtomatoes sautéed in olive oil rather than without.

On the other hand, stir-frying has been shown to significantly reduce the amount of vitamin C in broccoli and red cabbage.

Bottom Line: Sautéing and stir-frying improve the absorption of fat-soluble vitamins and some plant compounds, but they decrease the amount of vitamin C in vegetables.

Frying

Frying involves cooking food in a large amount of fat, usually oil, at a high temperature. The food is often coated with batter or bread crumbs.

It’s a popular way of preparing food because the skin or coating maintains a seal, which ensures that the inside remains moist and cooks evenly.

The fat used for frying also makes the food taste very good.

However, not all foods are appropriate for frying.

Fatty fish are the best sources of omega-3 fatty acids, which have many health benefits. These fats are very delicate and prone to damage at high temperatures.

Frying tuna has been shown to degrade its omega-3 content by up to 70-85%, while baking caused only minimal losses.

In contrast, frying preserves vitamin C and B vitamins, and it may also increase the amount of fiber in potatoes by converting their starch into resistant starch.

When oil is heated to a high temperature for a long period of time, toxic substances called aldehydes are formed. Aldehydes have been linked to an increased risk of cancer and other diseases.

The type of oil, temperature and length of cooking time affect the amounts of aldehydes produced. Reheating oil also increases aldehyde formation.

If you’re going to fry food, don’t overcook it, and use one of the healthiest oils for frying.

Bottom Line: Frying makes food taste delicious, and it can provide some benefits when healthy oils are used. It’s best to avoid frying fatty fish and minimize frying time for other foods.

Steaming

Steaming is one of the best cooking methods for preserving nutrients, including water-soluble vitamins that are sensitive to heat and water.

Researchers have found that steaming broccoli,spinach and lettuce reduces their vitamin C content by only 9-15%.

The downside is that steamed vegetables may taste bland. However, this is easy to remedy by adding some seasoning and oil or butter after cooking.

Try this easy recipe for steamed broccoli with suggested additions to improve the flavor.

Bottom Line: Steaming is one of the best cooking methods for preserving nutrients, including water-soluble vitamins.

Tips to Maximize Nutrient Retention During Cooking

Here are 10 tips to reduce nutrient loss while cooking:

  1. Use as little water as possible for poaching or boiling.
  2. Consume the liquid left in the pan after cooking vegetables.
  3. Add back juices from meat that drip into the pan.
  4. Don’t peel vegetables until after cooking them. Better yet, don’t peel at all to maximize fiber and nutrient density.
  5. Cook vegetables in smaller amounts of water to reduce loss of vitamin C and B vitamins.
  6. Try to finish cooked vegetables within a day or two, as vitamin C content may continue to decline when the cooked food is exposed to air.
  7. Cut food after rather than before cooking, if possible. When food is cooked whole, less of it is exposed to heat and water.
  8. Cook vegetables for only a few minutes whenever possible.
  9. When cooking meat, poultry and fish, use the shortest cooking time needed for safe consumption.
  10. Don’t use baking soda when cooking vegetables. Although it helps maintain color, vitamin C will be lost in the alkaline environment produced by baking soda.

Bottom Line: There are many ways to preserve the nutrient content in foods without sacrificing taste or other qualities.

Take Home Message

It’s important to select the right cooking method to maximize the nutritional quality of your meal.

However, there is no perfect method of cooking that retains all nutrients.

In general, cooking for shorter periods at lower temperatures with minimal water will produce the best results.

Don’t let the nutrients in your food go down the drain.

Franziska Spritzler has a BSc in nutrition and dietetics. She is a Registered Dietitian and Certified Diabetes Educator with expertise in carbohydrate-restricted diets for diabetes and weight management.


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Do Vegetables Lose Their Nutritional Value When Heated?

Frying these foods will give you a major boost in important disease-fighting vitamins

While frying can reduce the nutritional value of most foods, there’s an exception to the rule:

It’s a group of foods that contain significant amounts of the organic pigments called carotenoids, which studies indicate can help reduce the risk of several chronic diseases in humans, like heart disease, eye disease, and certain cancers.

When you expose carotenoids to high temperatures, energy from the heat breaks them down. This makes it easier for the body to absorb into your bloodstream, where it goes to work against disease.

And if you fry those foods in oil, as opposed to steaming or baking them, you absorb even more because carotenoids are fat soluble.

Where to find carotenoids

Carotenoids are prevalent throughout nature, but the three that are most common in our foods are:

  • Pro-vitamin A carotenoids like alpha carotene and beta carotene, which gives carrots and sweet potatoes that iconic orange color and has been shown to reduce the risk of age-related macular degeneration — a leading cause of vision loss in people over 50.
  • Lycopene, which provides most red-hued fruits, like tomatoes, pink grapefruit, and red peppers, their color. About 80% of the lycopene we ingest comes from tomato-based products, and over the last decade, studies have found that the lycopene in tomatoes could be linked to a reduced rate of prostate, lung, and stomach cancers.
  • Lutein, which is found in dark leafy greens like kale and Brussels sprouts and has also been shown to reduce the risk of eye diseases, like age-related macular degeneration.

A major nutritional boost

So just how much more of these disease-fighting carotenoids do you get by pan frying them in oil (not to be mistaken for deep frying, which is an entirely different method of cooking)?

We asked Guy Crosby, who has spent 30 years in the commercial food industry business and is now the editor for America’s Test Kitchen and teaches a food science course at the Harvard School of Public Health. You can learn more about him on his site “The Cooking Science Guy.”

As Crosby explains:

“In the fresh tomato most of these [carotenoid] pigments are all tied up with proteins,” Crosby told Business Insider. “If you cook the tomato you break down the bonds between the proteins and the pigments — the lycopene — and you absorb about four times more lycopene into your blood from cooked tomatoes than from fresh tomatoes.”

But wait, there’s more: Carotenoids fall under a class of vitamins called fat soluble vitamins, as opposed to water soluble vitamins like Vitamin C and some types of Vitamin B. This means that carotenoids will dissolve in fats, for example the fat in frying oil, just like the Vitamin B-6 in broccoli dissolves in water when you boil it.

“Since lycopene is soluble in oil, if you cook your tomato in olive oil, you’ll absorb two times more again above and beyond from what you absorb from cooking tomatoes without the oil,” Crosby said.

Now, if you’re watching your waistline, it’s important to limit the amount of fat you ingest daily. And frying anything is certainly going to up the fat content.

However, you don’t need very much oil to get this boost in nutrition — about three to five grams of fat is enough, which is equivalent to one teaspoon of olive oil.

Serving Vegetables Makes You More Thoughtful, Less Boring

Fact or Fiction: Raw veggies are healthier than cooked ones
Do vegetables lose their nutritional value when heated?

By Sushma Subramanian  March 31, 2009

Cooking is crucial to our diets. It helps us digest food without expending huge amounts of energy. It softens food, such as cellulose fiber and raw meat, that our small teeth, weak jaws and digestive systems aren’t equipped to handle. And while we might hear from raw foodists that cooking kills vitamins and minerals in food (while also denaturing enzymes that aid digestion), it turns out raw vegetables are not always healthier.

A study published in The British Journal of Nutrition last year found that a group of 198 subjects who followed a strict raw food diet had normal levels of vitamin A and relatively high levels of beta-carotene (an antioxidant found in dark green and yellow fruits and vegetables), but low levels of the antioxidant lycopene.

Lycopene is a red pigment found predominantly in tomatoes and other rosy fruits such as watermelon, pink guava, red bell pepper and papaya. Several studies conducted in recent years (at Harvard Medical School, among others) have linked high intake of lycopene with a lower risk of cancer and heart attacks. Rui Hai Liu, an associate professor of food science at Cornell University who has researched lycopene, says that it may be an even more potent antioxidant than vitamin C.

One 2002 study he did (published in the Journal of Agriculture and Food Chemistry) found that cooking actually boosts the amount of lycopene in tomatoes. He tells ScientificAmerican.com that the level of one type of lycopene, cis-lycopene, in tomatoes rose 35 percent after he cooked them for 30 minutes at 190.4 degrees Fahrenheit (88 degrees Celsius). The reason, he says: the heat breaks down the plant’s thick cell walls and aids the body’s uptake of some nutrients that are bound to those cell walls.

Cooked carrots, spinach, mushrooms, asparagus, cabbage, peppers and many other vegetables also supply more antioxidants, such as carotenoids and ferulic acid, to the body than they do when raw, Liu says. At least, that is, if they’re boiled or steamed. A January 2008 report in the Journal of Agriculture and Food Chemistry said that boiling and steaming better preserves antioxidants, particularly carotenoids, in carrots, zucchini and broccoli, than frying, though boiling was deemed the best. The researchers studied the impact of the various cooking techniques on compounds such as carotenoids, ascorbic acid and polyphenols.

Deep fried foods are notorious sources of free radicals, caused by oil being continuously oxidized when it is heated at high temperatures. These radicals, which are highly reactive because they have at least one unpaired electron, can injure cells in the body. The antioxidants in the oil and the vegetables get used up during frying in stabilizing the cycle of oxidation.

Another study published in the Journal of Agricultural and Food Chemistry in 2002 showed that cooking carrots increases their level of beta-carotene. Beta-carotene belongs to a group of antioxidant substances called carotenoids, which give fruits and vegetables their red, yellow, and orange colorings. The body converts beta-carotene into vitamin A, which plays an important role in vision, reproduction, bone growth and regulating the immune system.

The downside of cooking veggies, Liu says: it can destroy the vitamin C in them. He found that vitamin C levels declined by 10 percent in tomatoes cooked for two minutes—and 29 percent in tomatoes that were cooked for half an hour at 190.4 degrees F (88 degrees C). The reason is that Vitamin C, which is highly unstable, is easily degraded through oxidation, exposure to heat (it can increase the rate at which vitamin C reacts with oxygen in the air) and through cooking in water (it dissolves in water).

Liu notes, however, that the trade-off may be worth it since vitamin C is prevalent in far more fruits and vegetables than is lycopene. Among them: broccoli, oranges, cauliflower, kale and carrots. Besides, cooked vegetables retain some of their vitamin C content.

That said, research shows that some veggies, including broccoli, are healthier raw rather than cooked. According to a study in the Journal of Agricultural and Food Chemistry in November 2007, heat damages the enzyme myrosinase, which breaks down glucosinates (compounds derived from glucose and an amino acid) in broccoli into a compound known as sulforaphane.

Research published in the journal Carcinogenesis in December 2008 found that sulforaphane might block the proliferation of and kill precancerous cells. A 2002 study in The Proceedings of the National Academy of Sciences also found that sulforaphane may help fight the bacterium Helicobacter pylori, which causes ulcers and increases a person’s risk of stomach cancer.

On the other hand, indole, an organic compound, is formed when certain plants, particularly cruciferous vegetables such as broccoli, cauliflower and cabbage, are cooked. According to research in The Journal of Nutrition in 2001, indole helps kill precancerous cells before they turn malignant. And while boiling carrots was found to increase carotenoid levels, another study found that it leads to a total loss of polyphenols, a group of chemicals found in raw carrots. Specific polyphenols have been shown to have antioxidant properties and to reduce the risk of cardiovascular disease and cancer, according to a 2005 report in The American Journal of Clinical Nutrition.

Comparing the healthfulness of raw and cooked food is complicated, and there are still many mysteries surrounding how the different molecules in plants interact with the human body. The bottom line, says Liu, is to eat your veggies and fruits no matter how they’re prepared.

“We cook them so they taste better,” Liu says. “If they taste better, we’re more likely to eat them.” And that’s the whole idea.

Jessica Orwig    Feb. 1, 2016


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10 ways to get the most nutrients from your food.

Think raw is always best? Then you seriously need this.

Wondering if your nutrient intake stacks up? Check out these strategies to make sure you’re getting what you need.

Last year, I visited a good friend in Vermont. She and her family live in an old farmhouse on a bunch of land — enough for a massive garden, where she grows most of the plants they eat.

Picture rolling green hills, baskets of bright heirloom tomatoes, and little kids in galoshes. (Plus a layer of potting soil on most household surfaces).

My friend’s family eats from their own farm to table pretty much every night. She knows nutrients.
So it was really funny when she looked up from a steam pot one night and brazenly announced, “I like my green beans overcooked.” Like, limp. Like, wilted. Like you’re not supposed to like them.
The nerviness! The waste! The nutrients evaporating from those beans!

That’s what a lot of my “clean-food” obsessed peers would say, at least.

Is raw (or lightly cooked) really always best for your health?

I checked with three of Precision Nutrition’s nutrition experts: Ryan Andrews, Sarah Maughan, and Brian St. Pierre, all coaches in our men’s and women’s nutrition programs (and all credentialed beyond belief).

Turns out, the story is a lot more interesting than “cooked vs. raw”.
As you prepare, bite, chew, and digest, you create a series of mechanical and chemical changes that affect:

  • a food’s nutritional content (i.e. the nutrients it contains) and
  • each nutrient’s “bioavailability” (i.e. the degree to which it can be absorbed by your body).

This means:

  • Some nutrients are indeed best available when the foods containing them are eaten raw.
  • But other nutrients are best available when the foods containing them are cooked, or broken down by cutting or crushing, and/or eaten alongside other foods.

Here are the 10 best ways to get the most nutrition from your food.

1. Eat locally grown food soon after it’s been picked.

Eating locally grown and “straight from the earth” maximizes the vitamins and minerals (and deliciousness) you get from your produce.

Plucking them from the soil (or vine, or bush, or tree) means separating them from their nutrient source. The longer they’re separated, the more nutritional value they lose.

Some experts estimate that by the time you pick up a “fresh” fruit or vegetable at the grocery store, it may have lost 15-60 percent of many vitamins … unless you can buy and eat it within 72 hours of harvest.

Forget organic vs. traditional — that’s another debate altogether — when it comes to nutrients, local is king. That’s why hitting a local farm, or farmers market, ensures that you’re getting the most nutrient-dense product.

My only problem: I live in New Jersey. And not the “Garden State” part, either. Shop Rite (or “Shop Wrong”, as a neighbor calls it) is much more convenient than our cute but very limited farmer’s market.

Plus, there’s winter. Not a ton of freshly harvested produce to be had in the American northeast from November to June.

Thankfully, there are a lot of other ways to get the most nutrition from the food you eat — without having to sell your home and move out to the country.

2. Soak, chop, crush, blend.

These basics of food prep can make vitamins, minerals, and other compounds more available in a few ways:

  • Cutting up fruits and vegetables generally frees up the nutrients by breaking down rigid plant cell walls.
  • Crushing and chopping onion and garlic releases alliinase, an enzyme in these foods that helps form a nutrient called allicin. Allicin, when eaten, helps form other compounds that may protect us against disease.
  • Soaking grains and beans reduces phytic acid, which might — in part — block your absorption of iron, zinc, calcium, and magnesium.

If you’ve already been doing these things, great. Now you know why they work.
3. Store fruits and vegetables the right way.

When thinking about storage, balance two things:

  • Make it easy to eat your plants: Keep fruits and vegetables where you’re most likely to access them.
  • Slow down nutrient loss: Heat, light, and oxygen degrade nutrients.

That’s why you should store…

  • all vegetables — except those of the root variety — in the refrigerator until you need them.
  • all fruits except berries — this includes tomatoes and avocados — at room temperature away from direct light.
  • all cut fruits and vegetables with a squeeze of lemon juice on them and in an airtight container. (Cut produce rapidly oxidizes and vitamin C, an antioxidant, slows decay.)
  • all herbs — with their amazing phytonutrients — chopped up and frozen in an ice cube tray with water. (Maughan says she sees a lot of clients leave them unused — and eventually unusable — when they’re stored in the produce drawer.)

4. Eat most sources of water-soluble and heat-sensitive nutrients raw.
Heat breaks down vitamin B1, vitamin B5, folate, and vitamin C, so you get more of these when you eat certain foods raw.
Thus, foods like:

  • sunflower seeds, peas, beet greens, and Brussels sprouts (sources of vitamin B1),
  • broccoli, cauliflower, kale, and avocado (sources of vitamin B5),
  • spinach, turnip greens, broccoli (sources of folate), and
  • bell peppers, broccoli, and Brussels sprouts (sources of vitamin C)

are generally best eaten raw to maximize absorption of these water-soluble nutrients.
For example, raw spinach contains 3 times more vitamin C than cooked spinach.
You lose water-soluble B-vitamins and vitamin C when you boil them. So, if you’d like to cook these types of foods, cook them at low heat without exposing them to too much water.
This includes:

  • blanching;
  • steaming;
  • sautéeing;
  • roasting; and/or
  • microwaving.

5. Know which foods are best when cooked.
Baby carrots cooked with garlic, honey and thyme. Delicious!
There’s actually a wide range of nutrient loss from cooking — anywhere from 15 to 55 percent. In most cases, you lose the most nutrients by boiling in water.
But some foods actually deliver the most nutrients when cooked.
For example, cooking:

  • significantly increases bioavailability of lycopene, found in tomatoes. Research shows that lycopene increases by 25 percent when tomatoes are boiled for 30 minutes.
  • significantly increases the bioavailability of beta carotene, found in red/orange/yellow plants like tomatoes, carrots, sweet potato, and spinach. Cooking helps here by breaking down the plants’ cell walls.
  • denatures protein in eggs and meat, making them much more digestible.
  • makes iron and other minerals more available for absorption by decreasing oxalates, an acid that makes the minerals inaccessible by binding to them.
  • reduces certain harmful food components, such as cyanide (found in yuca) and possible anti-nutrients (found in grains and beans), making way for all the good stuff those foods have to offer.

Pro tip: If you do end up boiling veggies, keep the liquid for something like soup stock. This way you can eat those nutrients later and they’re not really “lost”.
As always, keep the big picture in mind: Boiled potatoes are still far better than French fries.

6. Pair food strategically to maximize nutrient absorption.

Many world cuisines put particular foods together. (Think of greens with lemon and olive oil in Italian cooking, or the complex spice blends in Caribbean, African, or South Asian cooking.)

Perhaps over 20,000-odd years of trial and error, cooks figured out instinctively that a “balanced” diet with a wide variety of foods is the best kind.

Putting the right foods together doesn’t just taste awesome, it also helps you absorb all nutrients in the foods you do eat.

salad

Here are a few examples.

  • Pair fat with fat.
  • Eat foods that contain the fat-soluble vitamins A, D, E, and K with dietary fats, which help dissolve the vitamins and ready them for absorption.

Therefore, foods like:

  • sweet potatoes, carrots, and squash (vitamin A),
  • eggs and mushrooms (vitamin D),
  • spinach, Swiss chard, and asparagus (vitamin E), and
  • kale, spinach, and broccoli (vitamin K)

all go better with 1-2 thumb-sized portions of healthy fats like:

  • mixed nuts;
  • avocado;
  • olive oil;
  • coconut oil; and/or
  • butter.

Cool note: Foods like salmon (which contains vitamin D), egg yolk and liver (vitamin A) and sunflower seeds (vitamin E) take care of themselves, since they’ve got their own healthy fat.
Pair iron with vitamin C.

Iron from non-meat sources is known as nonheme iron. Nonheme iron is not as well absorbed as heme iron, which is found in animal foods (such as red meat or dark poultry).
To absorb the nonheme iron from our plant friends up to 6 times better, pair them with foods rich in vitamin C.

This works in two ways:

  • Vitamin C can help the plant food “let go of” the mineral.
  • Vitamin C can block other dietary compounds that can inhibit absorption.

Therefore foods like:

  • spinach,
  • kale,
  • soybeans, and
  • lentils

all go better with:

  • a squeeze of lemon juice,
  • orange slices,
  • strawberries, or
  • chili peppers.

Think: Spinach salad with orange slices, strawberries, and a lemon juice vinaigrette. Or braised kale with chilis and a squeeze of lemon.

Pair iron and zinc with sulfur.

Finally, foods rich in iron and zinc are usually best eaten with foods rich in sulfur. Sulfur binds to these minerals and helps you absorb them better.

Therefore foods like:

  • liver, beef, and turkey (rich in iron)
  • oysters, beef, and turkey (rich in zinc)

all go better with garlic, onion, and egg yolks. (Visit your local deli to get Bubbie’s delicious chicken liver and egg yolk pâté.)

7. Keep it simple.

Don’t start creating spreadsheets to track all of this. Keep it simple and sane.
It’s still better to eat broccoli any way you can get it than to not eat it because it’s not “perfect”. As Brian “Voice of Reason” St. Pierre likes to say:

“60 percent of something is still better than 0 percent of nothing.”

It’s also important to factor in things like the quantity. For example, it’s a lot easier to eat five cups of cooked spinach (and all the nutrients therein) than five cups of raw spinach.

Sometimes the cooked and raw versions of a food are equally nutritious, just in different ways. For example, raw spinach might have more iron, but it also has more of the chemicals that block your absorption of iron.

Here’s a great rule of thumb in case you carry a little of the “to cook” or “not to cook” angst.

  • Water soluble vitamins (vitamins B and C) lose the most nutrients when cooked.
  • Fat soluble vitamins (vitamins A, D, E, K) lose the fewest nutrients when cooked.
  • Just eat some darn vegetables already.

8. Don’t discount frozen foods.

Does frozen broccoli have the same nutritional value as the stuff you just picked from the earth and ate raw? Maybe not. But how often do you eat raw, straight from the earth?

Research shows that processing can decrease a food’s vitamin C content by 10-90 percent. But the reality is that frozen or canned fruits and veggies come in handy when you’re busy. And a little vitamin C is better than none.

“I’ve seen too many clients opt for pizza because they think the frozen broccoli is the nutritional equivalent of cardboard,” Andrews says. Don’t be those people.
Remember, too that fiber isn’t affected much by freezing or canning. So eat your veggies … however you can get them.

9. If possible, try an animal source.

Many animal-based sources of vitamins and minerals are more bioavailable than plant-based sources (which may bind up vitamins and minerals chemically, or require a lot of steps to be converted to what our bodies prefer).

For instance, as we’ve noted, the iron you get from meat is more available for absorption than the iron you get from plants:

  • Heme iron, found in animal protein, is encased in hemoglobin molecules, which protect the nutrient from getting degraded by other nutrients and minerals in your GI tract. That means you’re absorbing the iron intact via gut cells that are specifically designed to take up the nutrient.
  • Nonheme iron, from vegetable sources like spinach, starts to change the minute it comes into contact with other stuff in your intestines, meaning you can only absorb a small fraction of it.

The same is true of many other vitamins and minerals, such as calcium or vitamin A.

We think that’s a great reason to enjoy a nice ribeye or sashimi platter from time to time.
If you’re an exclusively plant-based eater, remember you might have to work a little harder to pry some of those vitamins and minerals from your produce buddies.

10. Monitor your tolerance.

Nutrients don’t do you much good if you’ve got an undetected food intolerance that keeps you from absorbing them.

Unfortunately, not everyone tolerates raw foods very well even if they’re technically “better for you” sometimes.

If you have GI symptoms such as gas, bloating, or problems with your stool, consider an elimination diet to figure out what you’re not tolerating, and see a doc (nutrient deficiencies are more common than you might think).

Once you eliminate the foods that affect you the most, you can better optimize your nutrient intake.

What to do next

Remember: We don’t believe in wondering and worrying, or making too much of a fuss about your food choices. Keep things sane and simple.

If you’d like to improve your nutrient intake a bit, here are some simple steps you can take, in order of importance:

1. Just eat.
Choose a wide variety of whole foods. The fresher and more colorful, the better. Do that and you’re 99 percent there.

2. Eat a combo of raw and cooked dishes.
Focus on the foods you enjoy, the way you like them prepared. That way you’ll actually eat them.

3. Want to level up?
If you’re already eating at least 5 fist-sized servings of veggies each day, and want to improve your nutrient intake without supplements, consider:

  • eating more locally grown produce,
  • consuming that produce soon after harvested,
  • eating most vegetables raw or lightly cooked,
  • eating other vegetables cooked,
  • storing your fruits and veggies appropriately, and
  • pairing complementary foods to maximize absorption.

4. Look to traditional or ancestral cuisines for cues.

These diets have often figured out how to make the most of micronutrients. For instance:

  • The famed Mediterranean diet includes both crushed garlic and cooked tomatoes, as well as the antimicrobial powers of the phytonutrients in fresh herbs. They also enjoy nutrient-rich organ meats.
  • South Asian and Caribbean cuisine does the same and throws in some anti-inflammatory turmeric and ginger plus painkilling hot peppers for good measure.
  • Arctic cultures such as Scandinavians and Inuit make sure to eat fish liver to give them enough vitamin D during the long, sunless winters. (The famous Icelandic sheep’s head dish, or svið, offers phosphorus and vitamin A to brave eaters who consume the eyes.)

As you learn more about nutrition, look at world cuisines and notice what foods they traditionally put together in dishes and meals. There may be a reason beyond just taste!

5. Think you have a food intolerance and/or nutrient deficiency?
Get to the bottom of those through dietary analysis or nutrient testing and work with a healthcare professional to get them corrected.

By Lee Helland

References
Ishiwu Charles N., Iwouno, Jude O., Obiegbuna James E., Ezike Tochukwu C. Effect of Thermal Processing on Lycopene, Beta-Carotene and Vitamin C Content of Tomato [Var.UC82B]. Journal of Food and Nutrition Sciences. Vol. 2, No. 3, 2014, pp. 87-92.
Nutrient bioavailability – getting the most out of food. European Food Information Council. 2010.
Fielding JM, Rowley KG, Cooper P, O’ Dea K. Increases in plasma lycopene concentration after consumption of tomatoes cooked with olive oil. Asia Pac J Clin Nutr. 2005;14(2):131-6.