3. Is Soy Good for you (Part 2)
Effects of soybean peptide on immune function, brain function, and neurochemistry in healthy volunteers
Soybeans, an excellent source of dietary peptides, have beneficial effects on health. We investigated the effect of the soybean peptide on immune function, brain function, and neurochemistry in healthy volunteers. Near-infrared spectroscopy (NIRS) was used to analyze brain cerebral blood flow. The A and DA levels in the serum were analyzed by ELISA kit. The total number of leukocytes was recorded with a standard counter. Flow cytometry was used to assess lymphocyte subset levels. Cell numbers were upregulated in the group that had fewer leukocytes but downregulated in the group with more leukocytes. For the lymphocyte-rich type, lymphocyte counts tended to decrease, accompanied by an increase in granulocyte numbers. For the granulocyte-rich type, granulocyte counts tended to increase, but lymphocyte counts also increased. The numbers of CD11b(+) cells and CD56(+) cells increased significantly. Soybean peptide decreased the adrenalin level in plasma but increased the level of dopamine. Near-infrared spectroscopy showed significant increases in the amplitudes of θ, α-2, and β-L frequency bands after the ingestion of peptides. Soybean peptides can modulate cellular immune systems, regulate neurotransmitters, and boost brain function.
Soy Foods: Studies & Doctors Report Great Health Benefits & Debunk Myths.
Reports from Science Journals about the Health Benefits of Consuming Soy:
A 2010 report in The Journal of Nutrition is titled “Insights gained from 20 years of soy research.” Summary: “over the past 20 y an impressive amount of soy-related research has evaluated the role of these foods in REDUCING CHRONIC DISEASE RISK…
There are intriguing animal and epidemiologic evidence indicating that modest amounts of soy consumed during childhood and/or adolescence REDUCES BREAST CANCER RISK.
EVIDENCE ALSO SUGGESTS THAT SOY REDUCES PROSTATE CANCER RISK and inhibits prostate tumor metastasis…
there is suggestive epidemiologic evidence that soyfoods LOWER RISK OF CORONARY HEART DISEASE (CHD) independent of effects on cholesterol.
In clinical studies, soy favorably affects multiple CHD risk factors…
In regard to bone health… 2 large prospective epidemiologic studies found SOY INTAKE IS ASSOCIATED WITH MARKED REDUCTIONS IN FRACTURE RISK.
Soybean isoflavones also modestly alleviate hot flashes in menopausal women.
Finally, other than allergic reactions, there is almost NO CREDIBLE EVIDENCE to suggest traditional soyfoods exert clinically relevant adverse effects in healthy individuals when consumed in amounts consistent with Asian intake.”
Reference: Insights gained from 20 years of soy research.
According to the MedlinePlus website, care of the U.S. National Library of Medicine: “Soy in your diet can lower cholesterol. Many research studies support this claim. The U.S. Food and Drug Administration (FDA) agrees that 25 grams per day of soy protein may reduce the risk of heart disease. Health benefits of soy products may be due to their high levels of polyunsaturated fats, fiber, minerals, vitamins, and low saturated fat content.
Isoflavones that occur naturally in soy product may play a part in preventing some hormone-related cancers. Eating a diet that has a moderate amount of soy prior to adulthood may lower the risk of breast and ovarian cancer in women …
Dr Michael Greger’s 2016 youtube clip titled “Who Shouldn’t Eat Soy?” introduction: “How can soy foods have it both ways, pro-estrogenic effects in some organs (protecting bones and reducing hot flash symptoms) but anti-estrogenic effects in others (protecting against breast and endometrial cancer)?” is at https://www.youtube.com/watch?v=vltbg3NUSQs
In terms of bone health… The study clearly shows that the soy phytoestrogen prevents bone loss, and enhances new bone formation, in turn producing a net gain of bone mass… A significantly lower risk of bone fracture associated with just a single serving of soy a day — the equivalent of 5 to 7 grams of soy protein, or 20 to 30 milligrams of phytoestrogens. So, that’s just like one cup of soy milk — or, even better, a serving of a whole soy food, like tempeh or edamame, or the beans themselves…
Is there anyone who should avoid soy? Well, some people have soy allergies. A national survey found that only about 1 in 2,000 people report a soy allergy. That’s 40 times less than the most common allergen—dairy milk—and about ten times less than all the other common allergens—like fish, eggs, shellfish, nuts, wheat, or peanuts.”
A 2009 article in the peer-reviewed medical journal American Family Physician is titled “Soy: a complete source of protein“. The abstract states: “Soybeans contain all of the essential amino acids necessary for human nutrition and have been grown and harvested for thousands of years. Populations with diets high in soy protein and low in animal protein have lower risks of prostate and breast cancers than other populations. Increasing dietary whole soy protein lowers levels of total cholesterol, low-density lipoproteins, and triglycerides; may improve menopausal hot flashes, and may help maintain bone density and decrease fractures in postmenopausal women. There are not enough data to make recommendations concerning soy intake in women with a history of breast cancer. The refined soy isoflavone components, when given as supplements, have not yielded the same results as increasing dietary whole soy protein. Overall, soy is well tolerated, and because it is a complete source of protein shown to lower cholesterol, it is recommended as a dietary substitution for higher-fat animal products.”
From an article in Permanente Journal co-authored by several medical doctors: “Soybeans and foods made from soybeans are good sources of protein and may help lower levels of low-density lipoprotein in the blood and reduce the risk of hip fractures and some cancers…
A study in the Journal of the American Medical Association reported that women with breast cancer who regularly consumed soy products had a 32% lower risk of breast cancer recurrence and a 29% decreased risk of death, compared with women who consumed little or no soy. An analysis of 14 studies, published in the American Journal of Clinical Nutrition, showed that increased intake of soy resulted in a 26% reduction in prostate cancer risk.
Because of concerns over the estrogenic nature of soy products, women with a history of breast cancer should discuss soy foods with their oncologists. Also, overly processed, soy-based meat substitutes are often high in isolated soy proteins and other ingredients that may not be as healthy as less processed soy products (ie, tofu, tempeh, and soy milk)…”
From a 2016 report in the science journal ‘Nutrients‘ – “Soyfoods have long been recognized as sources of high-quality protein and healthful fat, but over the past 25 years these foods have been rigorously investigated for their role in chronic disease prevention and treatment.
There is evidence, for example, that they reduce risk of coronary heart disease and breast and prostate cancer. In addition, soy alleviates hot flashes and may favorably affect renal function, alleviate depressive symptoms and improve skin health…
Despite the many proposed benefits, the presence of isoflavones has led to concerns that soy may exert untoward effects in some individuals. However, these concerns are based primarily on animal studies, whereas human research supports the safety and benefits of soyfoods.
The British Dietetic Association (BDA) has put together this factsheet regards the health benefits of soya and dispelling the negative scare stories about it – see: https://www.bda.uk.com/foodfacts/soya_and_health.pdf