And Other Chicken Tales

There is a pervasive believe that chicken and fish are health foods. Now I can understand why people may think that fish is a health food (I don’t necessarily agree that it is), but is chicken healthy?  

I think this belief harkens back to the idea that protein is a health food and the only place to get quality, complete protein is from animal foods. And chicken, being on the leaner side of the equation, is the food of choice. This is likely why chicken consumption has, in fact, nearly doubled in the last few decades. Unfortunately, during the same time period, vegetable consumption has actually declined.

1. It Looks Better in Comparison to Beef

In epidemiological studies chicken often fares better than red or processed meats when it comes to disease outcomes like heart disease and cancer. However, just because this is true, doesn’t mean we can now make the leap that it is good for us. 

2. Chicken is not Very Nutrient Dense

It contains no fiber (a nutrient that 97% of Americans are deficient in), few micronutrients to speak of (iceberg lettuce has 2x the antioxidants) and it provides few nutrients relative to its calories. Ok so it does have some minerals like copper, selenium and zinc. But then again so does tofu. The industry brags that it is high in choline. But choline from eggs, chicken and dairy is a health risk as it is converted to trimethylamine (TMA) by the gut flora then oxidized into TMAO.  TMAO promotes atherosclerosis and is considered an independent risk factor for incident cardiovascular disease.

3. We Really Don’t Need Protein

I know this sounds like heresy, but, we really don’t. What we do need are amino acids. Any protein that we eat gets broken down into the amino acid constituents prior to absorption. Of the 21 or so amino acids only 9 are essential, i.e. we need to get them from our diet.  And even if we don’t get all 9 from our diet, we are constantly recycling protein from cell sloughing, dead gut bacteria and mucous etc.  Thus it is virtually impossible to create a protein deficiency. Eating preformed protein is a lot like eating the whole house. What we really need are just the bricks, and only some of them. On another note, the only organisms which can actually make amino acids are plants. Chicken is just secondhand protein.

4. All proteins are NOT created equal

Proteins come in an array of different amino acid profiles. Broadly speaking, plant foods have very different amino acid profiles than animal foods. For example, plant proteins contain higher amounts of arginine and lower amounts of lysine. Animal proteins are the opposite. Arginine is the precursor to nitric oxide, a gas that is released by the endothelium (cells that line the arteries) which is essential for maintaining arterial health and protecting us from plaque development and high blood pressure. This is why beans, higher in arginine, are better than beef or chicken (both low in arginine).

Studies in which animals are fed animal protein (in this case it was milk), showed increased build up of plaque in the arteries compared to being fed proteins high in arginine. When the protein was manipulated to have more arginine and less lysine, there was less build up. In another study, when animals were fed a high animal fat, animal protein diet, they had over twice the build up of plaque compared to a high fat, moderate protein diet. The group fed the low fat, low protein diet had no plaque. Also of interest was that the group on the high protein diet also had reduced progenitor cells (progenitor cells help to regenerate endothelial cells). 

Another amino acid that features predominantly in plant protein sources is glutamic acid. Higher intakes have been shown to be strongly associated with reduced blood pressure. It has been characterized as being “an amino acid of particular distinction” and multiple mechanisms can account for its favorable effect on BP. It can neutralize free radicals, and is a precursor to arginine. This may help explain the inverse associations seen with plant food consumption and blood pressure.

Human studies also support an association between animal protein consumption and heart disease. A large scale and well designed study on Swedish women found a 60 percent increased risk of heart disease in women adhering to a low-carb, high-protein diet. The results showed a gradual and consistent increased risk as the consumption of animal protein went up.

Yerushalmy and Hilleboe in their 22 country study reported that while total fat was not associated with heart disease, higher meat consumption was very strongly associated with increased risk. Other studies, have also reported that animal protein increased risk of myocardial infarction (MI), whereas plant protein decreased risk. A 2014 study which followed patients who had suffered from a MI found that a low carbohydrate diet that was high in animal protein increased mortality whereas a similar low carbohydrate diet which was high in plant protein was not associated with increased risk.  

So far, the only diet to show regression of arterial plaque is a diet that is free of animal products and rich in whole plant foods. Such diets have also been shown to improve diabetic control and lower blood pressure, even in the absence of weight loss.

5. Methionine and Cancer

Animal protein also has high amounts of methionine.  Certain cancers, including colon, breast, ovarian and prostate, have what scientists call an absolute methionine dependency, they need methionine in order to continue to grow. Several animal studies utilizing a methionine restricted diet have reported inhibition of cancer growth and extension of life-span. Methionine also has a pro-oxidant effect in that it promotes the formation of free radicals. Free radicals are implicated in accelerating the aging process. Guess which meat has among the highest methionine content? You guessed it, chicken (fish is a actually a little higher, eggs come in third). Beans on the other hand are quite low. 

6. IGF-1 and Insulin Secretion is Triggered by Animal Protein

Animal protein is also known to stimulate production of both insulin and IGF-1 (insulin-like growth factor). We need some growth factor, but higher blood levels of IGF-1 stimulates growth, proliferation, and spread of cancer cells. Elevated IGF-1 levels are linked to increased risk of all major cancers, including cancers of the breast, prostate and colon. IGF-1 is also suspected of playing a role in obesity, as it has an anabolic or growth effect on fat cells. Those that eat plant based diets (vegans) have significantly lower amounts of IGF-1 compared to both lacto-ovo vegetarians (who consume eggs and dairy) and meat eaters. 

Plant proteins stimulate glucagon production. This is a good thing as it inhibits production of cholesterol in the liver. Another mechanism that has been proposed as to why lower intakes of animal protein will help lower cholesterol is via the stimulation of the kinase GCN2, which in turn favors lower cholesterol production by the liver. 

And yes, you heard that correctly. Animal protein can trigger significant insulin production, almost as much as foods like rice and pasta. Eat white rice, insulin levels go up, add tuna or chicken to the rice and insulin levels will double. Intervention studies have also shown that when people abstain from eating animal foods fasting insulin levels will drop significantly. 

7. HCAs and AGEs

Because we need to cook chicken at high temperatures (yes it comes with a lot of fecal bacteria), cooked chicken meat has some of the highest levels of heterocyclic amines and polycyclic aromatic hydrocarbons.  These are potent carcinogens and are produced as a by product of cooking muscled meats at high temperatures. High consumption of these meats, especially when grilled, is associated with increased risk of aggressive prostate cancer as well as other cancers.

8. Advanced glycation endproducts, or AGEs, are also formed when meats are grilled, broiled, fried and barbecued. AGEs are implicated as playing a causal role in Alzheimer’s disease. They also promote inflammation and oxidation. Roasted, fried, broiled chicken contain some of the highest levels of these AGEs (bacon and burgers are also up there). Starchy foods on the other hand are very low in AGEs.

9. Arsenic

Arsenic, a known carcinogen, is also fed to poultry; it helps to control parasites and gives the meat that nice pink color. Sampling of chickens has found that nearly 75% carried detectable levels of arsenic as did 1/3rd of organic chicken. Arsenic can also contribute to heart disease, diabetes and mental decline and no amount is deemed safe. Rice is an unfortunate downstream victim as it is particularly good at absorbing arsenic from an environment contaminated by the poultry industry.

10. An Obesity Promoting Virus

In both cross-sectional and prospective studies, meat consumption is strongly associated with obesity and weight gain. A number of studies, however, have found that the association is much stronger for chicken consumption than for other meats. Data from close to 90,000 men and women across five European countries showed that higher intakes of animal but not plant protein was associated with subsequent weight gain for both men and women, but chicken was associated with 40% more weight gain compared to other meats. 

But why?

There are a couple of reasons why this could be. 

• Chicken meat is actually not that lean. Chickens not only have limited roaming space (if any), but they are also genetically bred to be obese. As one researcher put it, “In view of the obesity epidemic, chickens that provide several times the fat energy compared with protein seems illogical.”
• Most chickens are now infected with an adenovirus, a virus which promotes obesity. Birds infected with this virus have been shown to gain 50% more abdominal fat than unaffected birds in spite of eating the same amount of food. This virus has now spread to humans. Studies on humans have shown that those infected are more obese and more likely to gain weight when followed over time.  Another study found that those who tested positive for the virus were, on  average, 33 pounds heavier. Admittedly the evidence for this hypothesis is less than strong (i.e. while it has been shown to cause obesity in animals, human studies are more observational-you can’t knowingly inject humans with the virus), but it is one that warrants concern.

So is there anything commendable about chicken? I suppose if you raised and slaughtered your own you could bypass some of these problems (but not all). If you are stranded on a desert island and fried chicken falls from the sky, then by all means eat it. Yes, it can keep you alive. 

But taken together, these data would suggest that not only is chicken not healthy, it may actually be harmful, especially when eaten to the degree that we eat them in the US.  Nine billion chickens are killed annually in this country and most live their lives in total (and filthy) confinement. There is not a single law which protects them from abuse.

We live in a country where there is an abundance of food available. Choosing whole plant foods above chicken and other animal foods is not only more healthy, it is also a more sustainable and cruelty free way to live. 

PS clicking on the underlined words will take you to the referenced paper or abstract.