Adults require about 0.8 or 0.9 grams of protein per healthy kilogram of bodyweight per day. Does it matter if that protein is from animals or plants? Apparently yes.
The adverse effects associated with long-term, high protein-high meat diets may include disorders of bone and calcium balance, increased cancer risk, disorders of the liver, and worsening of coronary artery disease.
What about our kidneys? Harvard University researchers followed thousands of healthy women for more than a decade to look for the presence of excess protein in their urine, a sign that kidneys may be starting to fail. The researchers found three dietary components associated with this sign of declining kidney function: animal protein, animal fat, and cholesterol. Each is found in only one place: animal products. No association was found between kidney function decline and intake of plant protein or fat.
High animal protein intake may induce hyperfiltration, a dramatic increase in the kidney’s workload. Within hours of consuming meat, whether beef, chicken, or fish, our kidneys may rev up into hyperfiltration mode, whereas an equivalent amount of plant protein causes virtually no such stress on the kidneys.
Animal protein consumption also appears to trigger the release of insulin-like growth factor 1 (IGF-1), a cancer-promoting growth hormone. IGF-1 levels rise during childhood to power our development and diminish when we reach adulthood. Should the levels remain too high, however, our cells will constantly receive a message to grow, divide, and keep going and growing. Not surprisingly then, the more IGF-1 in our bloodstream, the higher our risk for developing some cancers. Animal protein appears to stimulate IGF-1 production whether it’s the muscle proteins in meat, the egg-white protein in eggs, or the milk proteins in dairy. After just 11 days of cutting back on animal protein, however, our IGF-1 levels may drop by 20 percent.
Watching our animal-to-plant protein ratio may be useful for cancer prevention. The largest diet and bladder cancer study found that a 3 percent increase in animal protein consumption was associated with a 15 percent increased risk of bladder cancer, while a 2 percent increase in plant protein intake was associated with a 23 percent decreased cancer risk.
Dr. Ornish and colleagues were able to demonstrate that a nearly exclusively plant-based diet allowed for an apparent reversal in early stage cancer growth, so the ideal animal-to-plant protein ratio may be quite low.
Image Credit: egal / Thinkstock. This image has been modified.
Popular Videos for Animal Protein
All Videos for Animal Protein
Dairy & Cancer
How do we explain the increased risk of prostate cancer but the decreased risk of colon cancer associated with dairy consumption?
Best Foods for Halitosis & Gingivitis
The best and worst foods for bad breath and gum inflammation.
Oxidized Cholesterol 27HC May Explain 3 Breast Cancer Mysteries
Oxidized cholesterol (concentrated in products containing eggs, processed meat, and parmesan cheese) has cancer-fueling estrogenic effects on human breast cancer.
Eggs & Breast Cancer
How few eggs should we eat to reduce the risk of prostate, ovarian, colon, and breast cancer?
Dietary Cholesterol & Cancer
The relationship between the consumption of eggs and other cholesterol-rich foods and cancers of the colon, breast, endometrium, pancreas, and throat.
Benefits of a Macrobiotic Diet for Diabetes
What happens when you add massive amounts of carbs to the daily diet of type 2 diabetics in the form of whole grains?
Benefits of Blueberries for Blood Pressure May Be Blocked by Yogurt
Researchers try to tease out what’s in dairy that interferes with the health benefits of berries and tea.
Prescription: Nutrition Episode 3 – Spilling the Beans
I team up with chef Rich Landau and public health nutritionist Tracye McQuirter to discuss the health benefits and preparation of beans.
The Risks of Shark Cartilage Supplements
Why are millions of dollars spent on shark cartilage supplements?
Does Chocolate Cause Acne?
What are the effects of dairy products, sugar, and chocolate on pimple formation?
Best Foods to Avoid for Eczema
Randomized double-blind controlled trials suggest excluding certain foods, such as eggs and chicken, can significantly improve atopic dermatitis.
Does Nutritional Yeast Trigger Crohn’s Disease?
Is the exaggerated reaction of many Crohn’s disease patients to baker’s, brewer’s, and nutritional yeast just a consequence of their inflamed leaky gut, or might it be a contributing cause?