The Truth about Red Meat
Over the past two decades, red meat has been increasingly blamed for everything from heart disease to cancer. Newspaper and magazine publishers love to plaster alarmist headlines about red meat across their front pages, but these claims are ill founded and misleading. In fact, an impartial review of the evidence reveals the truth about red meat: it’s one of the healthiest foods you can eat.
The following extract from Dr Chris Kresser, a respected and acclaimed Functional Medicine Doctor, is one of the most comprehensive and important I have ever read.
Why Red Meat Is Good for You
I think it’s safe to say that red meat has been unfairly blamed for the ills of Western society. But in case you have doubts about ordering the steak, here are some more reasons red meat is an extremely healthy and nutrient-dense choice.
Red meat is a rich source of vitamin B12, which is vital to proper functioning of nearly every system in your body. B12 deficiency can play a role in everything from aging, neurological disorders, and mental illness to cancer, cardiovascular disease, and infertility. Red meat also contains significant levels of other B vitamins, including:
• Pantothenic acid
• Vitamin B6
It’s crucial to get these vitamins from whole-food sources rather than relying on government fortification of processed foods, and red meat is one of the easiest ways to ensure adequate intake.
For people who don’t eat a lot of oily fish or receive a lot of direct sun exposure, red meat can contribute significantly to their overall vitamin D intake. Red meat also contains a vitamin D metabolite called 25-hydroxycholecalciferol, which is assimilated much more quickly and easily than other dietary forms of vitamin D. In populations with low sun exposure, meat has been shown to be protective against rickets, a degenerative bone disease caused by severe vitamin D deficiency. Interestingly, drinking milk with the same levels of vitamin D does not provide this same protection, indicating that the vitamin D in meat is uniquely absorbable and useful to the human body.
Red meat contains primarily heme iron, a form that is absorbed and utilised much more efficiently than the nonheme iron found in plant foods. Furthermore, even small amounts of meat can aid in the absorption of nonheme iron.
For people with iron overload conditions like hereditary hemochromatosis, it’s probably best to limit high-iron foods such as red meat, but for most of the population—especially those with iron-deficiency anaemia—the iron from red meat is beneficial. This is particularly important for women who are pregnant or looking to become pregnant, as iron is crucial for the growth and development of the fetal brain.
Red meat is an especially important source of zinc, because the other rich sources—organ meats and shellfish—are much less commonly consumed. As with vitamin D and iron, the zinc present in red meat is highly bioavailable, and even a small amount of red meat in the diet can increase zinc utilization from all sources. Zinc is an essential mineral that is an imperative part of many physiological functions, including structure in certain proteins and enzymes, and regulation of gene expression.
Those eating meat-free diets are at greater risk of zinc deficiency.
Finally, to round out this impressive nutrient profile, red meat contains significant levels of other vital minerals such as:
Why Red Meat Trumps White Meat
Some of the benefits I’ve mentioned thus far are not unique to red meat, but apply to animal flesh in general. For example, levels of B vitamins, vitamin D, and most of the trace minerals are just as high in white meat as in red. However, red meat does have significantly more B12, iron, and zinc than white meat, and those things alone are enough to set it apart. Where red meat really shines, though, is in its fatty acid profile. The fat of grass-eating “ruminants,” such as cows, comprises approximately equal parts of saturated and monounsaturated fat, with only a small amount of polyunsaturated fat. The unique ruminant digestive system ensures that these proportions stay relatively constant, regardless of what the animal eats. This makes red meat a better choice than poultry for those that cannot afford pasture-raised meat, because you will still be getting mostly saturated and monounsaturated fats.
What about Trans Fats?
Trans fats are one of the few food components that are widely accepted as being unhealthy, and for good reason. Industrial trans fats are created by pumping hydrogen molecules into liquid vegetable oil, changing the chemical structure and causing the oil to become a solid fat. Trans fats are generally considered to be especially harmful because they raise total cholesterol while lowering HDL cholesterol. However, as usual with conventional nutrition advice, there is far more danger to trans fats than simply the effect they have on cholesterol ratios.
However, it may surprise you to learn that many of the foods recommended on a Paleo or whole-foods diet contain trans fats as well. Dairy fat and meats from grass-eating ruminant animals contain significant amounts of trans fatty acids, and grass-fed animals have higher levels of these trans fats than grain-fed animals. In fact, your grass-fed steak contains about 0.5 to 1.4 g of trans fat per 28.3 g of total fat.
Does this mean we should cut out red meat if we want to reduce our risk of heart disease? Not at all! These naturally occurring trans fats in ruminant animal products are not at all harmful to our health and may actually reduce the development of many different chronic diseases.
CLA: How Is It Different from Industrial Trans Fats?
Naturally occurring trans fats are formed when rumen bacteria in the stomachs of ruminant animals (cows, sheep, etc.) digest the grass the animal has eaten and form trans-rumenic and trans-vaccenic acid via biohydrogenation of polyunsaturated fats in the grass. Conjugated linoleic acid, or CLA, is a trans-rumenic acid that is found abundantly in grass-fed meat and dairy products, and to a lesser degree in grain-fed products. It is also produced in our bodies from the conversion of trans-vaccenic acid (VA) from those same animal products.
Industrial trans fats have slightly different chemical structures than those trans fats found in beef and butter (specifically, the location of the double bond). CLA also contains both cis- and trans- bonds, whereas most industrial trans fats have only trans bonds. But these minor differences in structure lead to majorly different effects in the body, as has been shown in many clinical and epidemiological studies. While industrial trans fats are shown to increase the risk of heart disease, cancer, and obesity, CLA and other trans fats found naturally in animal products are thought to decrease the risk of those diseases.
Health Benefits of CLA
The major difference between CLA and industrial trans fats is the effect they have on heart disease and atherosclerosis. Several clinical and epidemiological studies have been performed, and meta analysis of these studies suggests that natural trans fats from animal products are not associated with any increased risk of heart disease. These studies have generally shown either an inverse or no association between natural trans-fat intake and heart disease across multiple geographical locations.
While there have been very few highly controlled clinical trials studying the effects of CLA and VA on heart disease and atherosclerosis, the few that exist also support the conclusion that these natural trans fats may reduce the risk of heart disease. In animal studies, CLA has demonstrated potent antiatherogenic effects, preventing fatty streak and plaque formation in the arteries of rodents by changing macrophage lipid metabolism. While more research in humans is needed, it seems that grass-fed dairy and meat products, high in both CLA and vitamin K2, are some of the best foods you can eat if you’re looking to prevent a heart attack.
TYPE 2 DIABETES
CLA may also be helpful in preventing the development and improving the management of type 2 diabetes. In rats, CLA has been shown to improve glucose tolerance and skeletal muscle insulin action. Research has also demonstrated that CLA may reduce hyperinsulinemia by increasing the production of adiponectin, a hormone that can lead to enhanced insulin action and improve insulin sensitivity. Epidemiological evidence suggests that there is an inverse association between CLA levels in adipose tissue and diabetes risk, further supporting the hypothesis that CLA may be involved in healthy insulin regulation.
CLA has even been shown to reduce the risk of cancer, in both experimental and case control studies. It appears to work primarily by blocking the growth and metastatic spread of tumours, controlling the cell cycle, and reducing inflammation. CLA is able to interrupt the omega-6 PUFA metabolic pathway for the synthesis of eicosanoids, preventing the inflammatory processes that promote cancer development.
You may have seen CLA supplements advertised as a weight loss promoter. Some research suggests that CLA can help reduce body fat and promote weight loss in overweight and obese individuals. In a few studies, dietary supplementation of CLA has been shown to increase lean body mass, reduce body fat mass, and improve overall body composition in overweight individuals. It is thought that CLA may promote improvements in body composition by increasing the breakdown and reducing the storage of body fat. That said, this reduction in body fat is small, so CLA may not cause significant weight loss in the way that supplement advertisers would suggest. But it certainly wouldn’t hurt in your weight loss efforts to increase your dietary CLA.
These studies certainly provide interesting food for thought about CLA’s possible health benefits. However, I think we need more high-quality human research before we can be certain about CLA’s role in human health and disease. The good news is that all of the foods CLA is present in are beneficial in other ways, so you’ll get enough CLA simply by emphasizing grass-fed meat and dairy products (assuming you tolerate dairy).
Red Meat Is a Great Dietary Source of CLA
Grass-fed dairy and meat are the best sources of CLA and VA. In fact, 100 percent grass-fed animal products contain from three to five times more CLA than products from animals fed grain. And since CLA is in the fat, the best sources will be fattier cuts of meat and bone marrow.
Some people may believe that supplementing CLA has the same potential benefits as eating a diet rich in CLA. I disagree and believe that these supplements could be potentially harmful. Most CLA supplements are derived from linoleic acid in safflower oil, and some studies have shown that CLA supplementation in humans can cause:
• Fatty liver
• Insulin resistance
Furthermore, CLA supplements have not demonstrated the beneficial effects seen from dietary intake of CLA in human trials. This may be due to the composition of synthetic CLA supplements; 50 percent of the product is an unnamed isomer and is an entirely different fatty acid than the CLA and VA found in meat.
It’s always better to get nutrients from food rather than supplements whenever possible, and CLA is no exception. So, if you’re looking for a heart-healthy, cancer-preventing diet, be sure to include plenty of grass-fed beef in your diet. (And don’t worry if your doctor thinks you’re crazy!).
Until next week, stay healthy