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May 7, 2014

Notes on meat

by Helene van den Berg

Meat contain 22% protein (much less than eggs). Meat contain several nutrients in a concentrated form, some of which are not readily available from plant sources. These nutrients, found in the lean portions of meat, are:

• iron
• vitamin B12, which is not available from plant sources (spirulina is an exception)
• lipids/fat ( except quinoa, nuts, seeds).

The body needs fat and should not be excluded from the diet. Fat supply 9 cal/gm , compared to 4cal/gm supplied by proteins and carbohydrates. To spare the body’s proteins from being used as fuel, an adequate intake of fats is essential. Fat is a good insulator and stores heat and protect the body in cold weather. Intermuscular fat stores supply immediate energy and you need fat for the digestion, absorption and transport of the fat soluble vitamins A, D, E and K.

Fat is needed for the development and growth of the brain and nervous systems. There are two types of fat: Saturated fats in animals are non essential fatty acids and are stored in the body, while the unsaturated fats in plants are the essential fatty acids involved in vital cell construction and maintenance functions and the development of the brain and nervous system.

The best meat comes from grass fed cattle: they carry only 5–10% carcass fat, compared to grain fed cattle (deprived of exercise) with 30% carcass fat – not to mention drugs and hormones added to the meat!.

NOTE: To avoid food poisoning (Salmonellosis) and worms (trichinosis) in contaminated meat, meat should be cooked/fried/grilled and hands and cooking utensils should be washed in preparing meat.

Avoid fatty meat. Organ meat contain most of the nutrients and have a higher biological value, BUT you need to know the source and how the animals have been raised! (Woolworths meat in SA are safe!). If people have gastrointestinal or bowel problems, muscle meats will aggravate these conditions, because they require more digestion and produce much waste and fermentation.

Processed meats, such as hot dogs, frankfurters, bacon, sausages, salami, ham etc. have a lot of artificial colorings, flavorings and preservatives (the law permits for up to 15% non-meat ingredients). Hot dogs/frankfurters could contain beef lips, snout, tail, blood , lung, spleen, tripe, and stomach. If chicken is added, it may contain chicken skin, chicken fat, giblets and chicken bone. Bacon has the highest concentrations of nitrites, followed by hot dogs, corned beef, ham and sausages.

Nitrites act on red blood cells producing methemoglobinemia, a form of hemoglobin that contains ferric iron, rather than ferrous iron, which has a decreased ability to bind oxygen and causes tissue hypoxia (not enough oxygen to tissues). Nitrites leads to severe poisoning and death may occur. Nitrites are also one of three ingredients (other two are amines and acid) which can combine in the stomach to form nitrosamines, which is one of the most formidable carcinogens (cancer producing) yet discovered. For nitrosamines to form in the stomach, you must ingest nitrites and amines at the same time e.g. ham or salami (nitrites) and beer or wine (amines). Therefore avoid all precut packaged meats!.

HOW VITAMINS ARE AFFECTED IN MEAT with COOKING, PROCESSING and STORAGE:

Protein and mineral content is relatively stable in red meat, regardless of how you cook it. Vitamins however are affected by cooking methods, especially the water soluble vitamins, like the B vitamins. Water-soluble vitamins can drop, due to high temperatures, long cooking times, cooking in an alkaline solution or cooking in water. Fat-soluble vitamins can leach out of your red meat if you cook the meat in large amounts of fat. The best cooking method for red meat to minimize vitamin losses is, stir frying – it involves short cooking times and uses only small amount of oil and liquid (use not too high temperatures). Use grass-fed meat to start off with more vitamins and minerals and less fat. If you cook red meat in oil or water, use this oil and water in a sauce or soup so you don’t lose out as many nutrients.

Roasting provide better vitamin retention than braising(simmering), and stewing destroys the most vitamins (smaller pieces and bigger surface area where vitamin loss occur). Longer cooking times destroy harmful bacteria BUT also useful vitamins.

Freezing meat: There is little or no loss of nutrients during the frozen storage – except for Vitamin E. The losses incurred in frozen meat mostly take place when the meat is thawed and the juices are exuded containing soluble proteins, vitamins and minerals.

Cooking meat: The loss of Thiamine ( vitamin B1) in meat after roasting was 38–50%, after broiling – 20–30%, after stewing – 49%. The loss of Riboflavine (B2) and Niacin (B3) varies from 15–48%. Thiamine (B3) destruction is doubled for each 10 degree rise in temperature.

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

Dehydration: Losses of vitamins in dehydration of meat:
Beef – Thiamine(B1) 24%; Niacin(B3) 8%; Panthotenic acid(B5) 32%; Riboflavin(B2) no loss.
Pork – Thiamine(B1) 37%; Niacin(B3) 8%; Panthotenic acid(B5) 27%; Riboflavin(B2) no loss.

Vitamins that are not present in meat are: Vitamin A, Vitamin C, vitamin D, alpha- and beta carotene, tocopherol (except alpha tocopherol), lycopene etc.

When meat are braised, the highest losses occurs in group B vitamins. Meat is the best supplier of group B vitamins to our diet – especially Vitamin B12, which is hard to acquire from a vegetarian diet. Cooking doesn’t destroy a significant amount of vitamin B12 BUT for vitamins B1, B3, B5 , B6 , folate and vitamin K it is between 25–57%!.

The highest vitamins in meat are B3 and B6. After cooking, 1 pound of beef will shrink to
226 gms and will provide 80% of your daily required amount of vitamin B3. A cup of raw peanuts can provide 88% and provides 25% of vitamin B6!. After cooking , 226gms of beef will still provide 60% of your B6 daily value. One and a half bananas would do the same.

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

Conclusion:
* Proteins, minerals and cholesterol are mostly retained through cooking.
* Vitamins loss may be as big as 50%. Compared to vitamins in the foods that are usually consumed raw, cooked meat doesn’t contain significant amounts of vitamins. The exception is vitamin B12.
* Commercial canning results in vitamins loss similar to home cooking.
* Dehydration results is the least loss of vitamins of all ways of cooking.

Word of caution to BARBEQUE LOVERS!!

Grilling meats – grilling meat can be healthy, because some of the meat’s saturated fat content is reduced BUT it also present a health risk. Two types of carcinogenic compounds are produced by high-temperature grilling:

  • Heterocyclic amines (HCAs) – HCAs form when meat is exposed to a flame or very high temperature surface. HCAs cause DNA mutation and may be a factor in developing certain cancers.
  • Polycyclic aromatic hydrocarbons (PAHs) – PAHs form in smoke that’s produced when fat from the meat drips on the hot coals of the grill and is linked to certain cancers.

HCA and PAH content in meat can be reduced by altering your grilling method:

  • Select leaner meats – less likely to drip fat on the grill.
  • Marinate meats before grilling – it forms a protective barrier for the meat juices and reduce HCA formation with 90%.
  • Grill at lower temperatures.
  • Prevent flare-ups: turn meat frequently.
  • Don’t overcook meats – well-done or burnt meats contain higher levels of HCAs.
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