Cooking meat: what happens to the nutrients?

What method of cooking meat preserves the most vitamins and minerals in it? What vitamins are in meat? What happens to the proteins, and does the biological value of meat reduce after cooking?

 

Numerous studies have been made to determine what happens to the vitamin, mineral, and protein content of different meats after cooking and commercial processing. It was a complicated task, since the content of nutrients and proteins, as well as protein composition, vary greately for different types of meat and even for different cuts of the same animal. That's why scientific literature provides range, rather than a single number, when referring to the nutrients loss. Let's look at the most popular ways of cooking and the most important vitamins that meat may supply to the diet.

Effects of cooking and processing on vitamins in meat

Roasting and broiling provide better vitamin retention than braising, and stewing destroys the most vitamins. It isn't surprising, is it? As a general rule, the smaller the pieces, the bigger the surface area where vitamin loss occurs. Longer cooking times destroy both harmful bacteria and useful vitamins in meat.

Cooking meat: Braising, roasting, broiling, and stewing

The loss of Thiamine (B1) in meat after braising and roasting was 38% to 50%, after broiling - 20% to 30%, after stewing - 49%. The loss of Riboflavine (B2) and Niacin (B3) varies from 15% to 48%.

Thiamine (B1) destruction is doubled for each 10 degree rise in temperature, however there is a tenfold increase in the rate of destruction of heat-resistant bacteria.

Cooking meat: Canning

The vitamin retention in pork and beef during commercial canning is similar to that of household cooking. After 293 days of storage, a slight loss of vitamins occurs - for example, thiamine retention fell from 60-70% to 52%.

Cooking meat: Dehydration

The following percentage losses of vitamins were found in the dehydration of meat:

  • Beef: Thiamine (B1) 24%, Niacin (B3) 8%, Pantothenic acid (B5) 32%, Riboflavin (B2) - no loss.
  • Pork: Thiamine (B1) 37%, Niacin (B3) 8%, Pantothenic acid (B5) 27%, Riboflavin (B2) - no loss.

Cooking meat: effects on protein

Cooking reduces the biological value of beef, although not significantly. More work is needed to evaluate properly the nutritional value of meat proteins.

Comparison of vitamin content in bottom round beef before and after braising

Let's go to www.NutritionData.com and see what happens to the "Beef, round, bottom round, separable lean and fat, trimmed to 1/8" fat" after it gets braised as a single piece.

There are vitamins that that don't suffer any losses: Vitamin A, Retinol, Alpha Carotene, Beta Carotene, Beta Cryptoxanthin, Lycopene, Lutein+Zeaxanthin, Vitamin C, Vitamin D, Beta Tocopherol, Gamma Tocopherol, Delta Tocopherol. Why? Because they are not present in meat to begin with.

Table 1 is a comparison of vitamin content before and after braising.

Table 1. Vitamin content in 1 pound of bottom round beef before and after braising
Vitamins Amounts Per 1 lbs before cooking Units %DV Amounts Per 1 lbs after cooking Units %DV Loss of vitamins
 
Vitamin B6 2.8 mg 139% 1.2 mg 60% 57%
Thiamin (B1) 0.4 mg 25% 0.2

mg 14% 50%
Folate 49.9 mcg 12% 28.1 mcg 7% 44%
Niacin (B3) 27.5 mg 138% 16.1 mg 80% 41%
Pantothenic Acid (B5) 2.7 mg 27% 1.8 mg 18% 33%
Vitamin K 6.4 mcg 8% 4.8 mcg 6% 25%
Betaine 57.6 mg   46.1 mg   20%
Vitamin E (Alpha Tocopherol) 1.6 mg 8% 1.3 mg 7% 19%
Choline 392 mg   351 mg   10%
Vitamin B12 5.6 mcg 93% 5.1 mcg 85% 9%
Riboflavin (B2) 0.5 mg 29% 0.5 mg 29% 0%

As shown in Table 1, the highest loss occurs in group B vitamins. Meat is often positioned as the best supplier of group B vitamins to our diet. It is very true for Vitamin B-12. This vitamin is hard to acquire from a vegetarian diet, is better digestable when it comes from meat, and cooking doesn't destroy a significant amount of it. For the other B vitamins, the picture is not as bright.

The vitamin content of foods should be compared in its ready-to-eat state. If you don't eat raw meat, it is irrelevant to you how many wonderful vitamins it boasted to provide before you cooked it. For example, Thiamine (Vitamin B1) is so easily acquired from flaxseed and wheat bran, that you need a teaspoon of any of them to match its content in a half-pound of cooked meat.

The highest vitamins in meat are B3 and B6, so it will be a fair comparison to look at these two vitamins and their sources.

Niacine (Vitamin B3): After cooking, 1 pound of beef will shrink to 226 grams and will provide 80% of your daily required amount of Vitamin B3. That's a big portion! One cup of raw peanuts beats that by providing 88%. In addition, it provides 25% of Vitamin B6.

What about Viitamin B6? After cooking, 226 grams of beef will still provide 60% of your B6 daily value. One and a half bananas would do the same.

Most of the group B vitamins, with the exception of B12, can be easily delivered by sources other than cooked meat.

Health-related concerns: saturated fat and cholesterol

While small amount of saturated fat is essential for the body to function, meat contains amounts that increase your chances for heart disease. Some styles of cooking reduce content of saturated fats in meat as they get transferred into the drippings. Others, like stewing and braising, do not provide significant reduction.

It's interesting that the food industry usually reports fat content in meat by percentage of weight. It is very deseptive to the consumers because dietitians set the target as a percentage of calories from fat in the daily diet. The leanest cuts of beef contain 30% of calories from fat, the leanest cuts of chicken - 20%. Both of these values are much higher than grains, vegetables, beans and fruit, which are comfortable below 10%.

Meat, like all animal products, contain cholesterol. Every 100 mg of cholesterol you eat adds roughly 5 points to your cholesterol count. A piece of round beef that we considered in the example above will add a whopping 540 mg of cholesterol to your daily diet. Cooking meat will not destroy cholesterol, it will increase its contents per gram of the ready product, as the water evaporates during cooking.

Conclusion

Different methods of cooking meat result in various loss of nutrients:

  • Proteins, minerals, and cholesterol are mostly retained.
  • Some loss of fat occurs when meat is grilled or broiled.
  • Vitamins loss may be as big as 50 percent. Compared to the vitamins in the foods that are usually consumed raw, cooked meat doesn't contain significant amounts of vitamins. The exception is Vitamin B-12.
  • Commercial canning results in vitamins loss similar to home cooking
  • Dehydration results is the least loss of vitamins of all ways of cooking.

The goodness of protein from meat comes with the load of fat and cholesterol. Just like everything else, except greens and vegetables, meat should be eaten in moderation or not consumed at all.

Sources:

1. Melville Sahyun, M.A., Ph. D. Proteins and amino-acids in nutrition

2. Neal Barnard, M.D. Food for life: How the new four food groups can save your life

3. www.NutritionData.com

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