The Paleo Answer is a book by Dr. Loren Cordain, the professor who gained fame for writing The Paleo Diet. This post has notes featuring the results of some of the studies cited in the book.
• A study showed that a group of Australian Aborigines lost 16.5 pounds and reduced their triglycerides by 72 percent when they returned to their traditional diet.
• A study found that the paleo diet was more satiating than the Mediterranean diet because it caused greater changes in leptin.
• A study showed that a group going on a paleo diet lost weight, reduced their waist size, and experienced reductions in blood pressure and plasminogen activator inhibitor.
• A study of inactive subjects showed that the paleo diet led to improvements in blood pressure, arterial function, insulin, and triglycerides.
• A study of patients with type 2 diabetes found that the paleo diet resulted in improved weight loss, waist size, blood pressure, HDL cholesterol, triglycerides, blood glucose, and hemoglobin A1c.
• A study found that adding high-saturated-fat beef drippings to the diet improved the total cholesterol/HDL cholesterol ratio.
• A meta-analysis found that when carbohydrates replaced saturated fats, carbs increased the risk for heart disease by increasing blood triglycerides and lowering HDL cholesterol levels.
• A meta-analysis found that red meat consumption was not associated with either heart disease or type 2 diabetes, whereas processed meats led to a 42 percent greater risk.
• The average dietary saturated fat intake of 229 hunter-gatherer societies was 15.1 percent of calories.
• If nitrites are present, morpholine is transformed into N-nitrosomorpholine, a cancer-causing agent.
• A series of population-based studies have demonstrated strong associations between artificial sweeteners and obesity.
• A study showed that rats consumed more food and gained more weight when artificial sweeteners were added to their diet.
• A series of experiments showed that even low doses of aspartame given to rats led to increased cancer rates.
• Animal experiments found that saccharin, acesulfame, and aspartame caused DNA damage in the bone marrow of mice.
• A study of 59,334 pregnant women in Denmark showed that consumption of artificially sweetened soft drinks significantly increased the risk for pre-term delivery.
• Restriction of dietary advanced glycation end-products lowers markers of oxidative stress and inflammation.
• Fructose produces ten times more advanced glycation end-products than glucose.
• An analysis of 229 hunter-gatherer societies showed that 73 percent of them consumed 46 percent or more of their daily calories as animal food.
• A meta-analysis that compared overall death rates between 27,808 vegetarians and 48,364 meat eaters showed no significant differences between vegetarians and non-vegetarians in mortality from cerebrovascular disease, stomach cancer, colorectal cancer, lung cancer, breast cancer, prostate cancer, or all other causes combined.
• An analysis of 33,883 vegetarians showed that mortality from circulatory diseases and all causes was not significantly different between vegetarians and meat eaters.
• A study of ninety-five vegetarians showed that 77 percent of lacto/ovo vegetarians and 92 percent of vegans were deficient in vitamin B12.
• A study of 231 lacto/ov vegetarians and 232 vegans showed that 73 percent of the vegans and 24 percent of the lacto/ovo vegetarians had vitamin B12 deficiencies.
• A study found that long-term lacto/ovo vegetarian diets impair vitamin B12 status in pregnant women, which can cause deficiencies in the fetus and nursing infant.
• Studies of vegetarians and vegans show that the less animal food they eat, the higher their blood concentrations of homocysteine are.
• A meta-analysis showed that for each 5 micromol/L rise in blood homocysteine levels, the risk for cardiovascular disease events increased by approximately 20 percent.
• A study of 268 lifelong Indian vegetarians with cardiovascular disease showed that heart disease was higher in vegetarians and that they had lower blood levels of vitamin B12.
• A review of 1,627 articles on high blood levels of homocysteine and low blood levels of vitamin B12 concluded that high homocysteine is a risk factor for dementia.
• A study found that a high dietary intake of folate makes B12 deficiencies worse by increasing blood concentrations of homocysteine.
• A study of 9,420 vegetarians and 1,126 vegans found that vegans had a higher fracture risk.
• More than a dozen studies have identified low B12 or high homocysteine blood levels as risk factors for osteoporosis.
• A study of 559 elderly women in Japan showed that supplementation of vitamin B12 and folate (not folic acid) reduced the number of hip fractures.
• A study of 172 men and 223 women who were unable to conceive showed that 36 percent of men and 23 percent of women had vitamin B12 deficiencies.
• A study found that within only six weeks of consuming a vegetarian diet, 78 percent of normally cycling women ceased ovulating.
• A study in Europe showed that 80 percent of vegans and 25 percent of lacto/ovo vegetarians suffered from iodine deficiency.
• A meta-analysis showed that moderate childhood iodine deficiency lowered IQ by 13.5 points.
• A study of 9,420 vegetarians and 1,126 vegans showed that blood concentrations of vitamin D were highest in meat eaters and lowest in vegans and vegetarians.
• A study of ninety-three German vegans found that 58 percent suffered from vitamin B6 deficiencies.
• Epidemiological studies show that vegans who do not supplement with omega-3 fatty acids are deficient in both EPA and DHA.
• Randomized clinical trials in patients with preexisting heart disease show that omega-3 fatty acid supplements significantly reduce cardiovascular events.
• Studies of vegans show that their blood taurine levels are 22 percent lower than in meat eaters.
• A study showed that eight weeks of EPA and DHA supplementation restored normal platelet function in a group of eighteen lacto/ovo vegetarians.
• A ranking of foods containing the thirteen nutrients that are usually deficient in the diets of the American population (from most nutrient-dense to least nutrient-dense):
1. Fresh vegetables
2. Seafood
3. Lean meats
4. Fresh fruits
5. Whole milk
6. Whole grains
7. Nuts and seeds
• A study found that peptic ulcer patients following the Sippy Diet (a diet focusing on regular intake of milk and cream) had a fatal heart attack rate of 42 percent.
• An epidemiological study involving forty countries demonstrated that milk had the highest relationship with cardiovascular death rates for any food or nutrient examined.
• A meta-analysis involving twenty-six studies of more than twenty-thousand participants showed that calcium supplementation significantly increased the risk for heart attacks and sudden death.
• A study showed that high dietary calcium-to-magnesium ratios are a better predictor of heart disease than high calcium intake by itself.
• Studies of hunter-gatherers show that the dietary calcium-to-magnesium ratio was close to 2:1, while milk has a much higher ratio of 12:1
• A study involving 24 eight-year-old boys found that a high-milk diet worsened their insulin response by almost 100 percent.
• An experiment in Australia showed that low-glycemic-index, high-protein diets reduced symptoms of acne.
• Epidemiological studies have identified cow’s milk as a major risk factor for type 1 diabetes.
• Fifteen epidemiological studies show that milk elevates IGF-1 in the bloodstream. Meta-analyses show that high blood levels of IGF-1 strongly increase the risk for prostate and breast cancer.
• Studies show that milk drinking increases the risk of ovarian cancer.
• Cow’s milk contains estrone sulfate, which can raise the blood concentration of female hormones in men.
• A study found that 50 percent of all infants and young children who were allergic to milk later developed allergies to a wide variety of other foods before puberty.
• A study showed that infants whose mothers drank milk became colicky.
• A meta-analysis showed that men who consumed the highest quantities of dairy products had an 80 percent greater risk of developing the disease than did men who ate the lowest amounts.
• A study of Japanese men showed that those who consumed more than 16 ounces of milk daily had a 130 percent greater risk of Parkinson’s disease than those who did not drink milk.
• Epidemiological studies show that lactose and galactose are involved in premature cataract formation.
• A series of studies in Iran showed that excessive consumption of whole wheat flatbread caused zinc deficiency in boys, which resulted in dwarfism.
• Animal experiments show that whole-grain oats and wheat worsen health even more than refined grains.
• A study showed that people who consumed 60 grams of wheat bran daily for thirty days had an increased elimination of vitamin D from the intestines.
• Experiments show that the wheat germ agglutinin found in wheat can bypass the gut barrier and disrupt cellular function.
• Animal and human studies indicate that chia seed products may promote leaky gut and chronic systemic inflammation.
• Amaranth contains a lectin called ACA that is a potent promoter of intestinal cancer cell growth.
• Quinoa has a high saponin content, which increases intestinal permeability.
• Experiments have shown that buckwheat can cause damaging skin reactions.
• Studies show that raw or undercooked red kidney beans can cause nausea, vomiting, abdominal pain, severe diarrhea, muscle weakness, or inflammation of the heart.
• Raw kidney beans are toxic to rats when fed at more than 37 percent of their daily calories.
• Laboratory experiments show that the lectins found in beans pass through the gut barrier and can disrupt normal cell function.
• Studies in animals and human tissue show that legume saponins can cause ruptures in red blood cells.
• A study showed that when subjects with an average age of sixty-one were given 30 grams of soy daily for three months, they developed symptoms of low thyroid function.
• A meta-analysis of forty-seven studies demonstrated that soy or soy isoflavone consumption in women caused follicle-stimulating hormone and luteinizing hormone to fall by 20 percent.
• A research paper indicates that soy isoflavones may be risk factors for autism due to their ability to impair iodine metabolism and thyroid function.
• Lima beans and cassava contain cyanogenetic glycosides, which are turned into poisonous hydrogen cyanide when digested.
• Peanut oil causes arterial plaques to form in rats and primates.
• Potatoes contain glycoalkaloid saponins that may aggravate intestinal bowel diseases.
• Two human studies have shown that diets high in potato consumption increase the inflammatory marker IL-6.
• Alfalfa sprouts contain L-canavanine, which can cause lupus.
• Foamy soft drinks contain quillaja extract, which can worsen autoimmune diseases.
• Tomatoes contain saponins, which can cause leaky gut and worsen autoimmune conditions.
• Chili peppers contain capsaicin, which causes intestinal leakage.
• A meta-analysis showed that high blood folate levels were associated with an increased risk of prostate cancer.
• A study of 70,656 postmenopausal women showed that dietary folate intake was positively associated with breast cancer risk.
• A study of 1,021 men and women over a ten-year period found that folic acid was associated with higher risks of having three or more cancers.
• A meta-analysis of 118,765 people and nine randomized controlled trials showed that vitamin E increased the risk of hemorrhagic stroke by 22 percent.
• Low vitamin D status increases the risk for sixteen cancers, autoimmune diseases, cardiovascular disease, type 2 diabetes, hypertension, mental illness, osteoporosis, and infectious diseases.
• Chlorine combines with organic matter to produce trihalomethanes, which increase the risk of bladder and colorectal cancers.
• A study involving 1,455 adults showed that even low blood levels of BPA increased the risk for cardiovascular disease and diabetes.
• Very high protein diets (187 to 270 grams per day in men and 134 to 246 grams per day in women) can lead to protein toxicity.
• High maternal protein intake increases the risk of fetal mortality.
• A study showed that low-glycemic-index diets led to a 50 percent reduction in the number of women who required medication to control their blood sugar during pregnancy.
• Studies suggest that sufficient consumption of fish during pregnancy may help prevent postpartum depression.
• An analysis of cancer rates in the Inuit from 1950 to 1980 found that breast cancer was absent before 1966.
• A meta-analysis of ten studies involving more than 575,000 subjects showed that high-glycemic-diets increase the risk for developing breast cancer.
• Animal experiments show that omega-6 fatty acids from vegetable oils stimulate breast cancer growth, while omega-3 fatty acids inhibit breast cancer growth.
• A large meta-analysis showed that omega-3 fatty acids help prevent breast cancer.
• A randomized trial involving 773 subjects demonstrated that high-protein/low-glycemic-index diets were the most effective in keeping weight off.
• A study of 827 children showed that those assigned to low-protein/high-glycemic diets became significantly fatter, whereas overweight and obese children assigned to high-protein/low-glycemic diets lost significant amounts of weight.
• Research has found that diets that avoid wheat and dairy can help reduce symptoms of schizophrenia.
• An epidemiological analysis found that populations eating little or no wheat/rye/barley had very low rates of schizophrenia.
• A review of seven trials found that elimination of wheat and dairy could reduce symptoms of autism.
