Soy what is it

Another meta-analysis of 16 studies found that soy isoflavone supplements had a small and gradual effect in weakening menopausal hot flashes compared with estradiol human estrogen. However, the authors noted weaknesses in the analysis due to a small number of participants and high variability in study design.

This area needs further research as questions remain about a possible benefit of soy. Results are conflicting, potentially due to variation in the types of soy preparations used, the quantities given, and for how long they are used. In some tissues and in some people, they may block the action of estrogen. Studies so far have not provided a clear answer. Some have shown a benefit with soy consumption and breast cancer while others show no association. In animal and cell studies, high dosages of isoflavone or isolated soy protein extracts tend to stimulate breast cancer growth.

Women from Asian countries appear to receive greater protective benefit from breast cancer with high soy intakes than American and European women, but this may simply be a difference in the amount of soy consumed.

The Breast Cancer Family Registry was a prospective study following 6, women diagnosed with breast cancer and living in the U. Another prospective study followed 1, American women who were breast cancer survivors for six years. The incidence of prostate cancer is highest in Western countries and lowest in Asian countries, where soy foods are a regular part of the daily diet. In addition, observational studies have found an increased risk of prostate cancer in Chinese and Japanese men who move to Western countries and adopt a Western diet, but not in those who continue eating a traditional diet.

In a meta-analysis of 30 case-control and cohort studies from the U. A review of eight randomized controlled trials examined the effects of soy in men with or at risk of developing prostate cancer. Two of these studies found that isoflavone supplements or dietary soy protein reduced the risk of prostate cancer in men at high risk of developing the disease.

However, none of the studies found a significant effect on prostate specific antigen PSA levels. PSA is a protein produced by the prostate gland that is used to detect prostate cancer. There were no adverse effects reported with soy supplementation. The authors discussed limitations of the review including the small number of participants, the short duration of studies less than one year , and variation in dosages and types of soy given. Menopause has been linked with changes in mood and memory impairment.

Thus, research has raised the possibility that eating soy foods might help prevent age-related memory loss or decline in thinking skills. Trials have yielded contradictory results, with some showing a benefit with soy isoflavone supplementation [28, 29] and others showing no benefit. However the results overall were mixed, with other studies not demonstrating a benefit.

This may have been due to differing dosages given or the types of cognition tests used. One large study in men found a detrimental effect on cognitive function. In a prospective cohort study of more than 3, Japanese-American men living in Hawaii, the highest intakes of tofu eaten almost daily at midlife ages were significantly associated with greater cognitive impairment and brain atrophy in late life compared with men with the lowest tofu intakes almost never eaten.

Because of this, the researchers stated that the findings were too preliminary to make recommendations. Soy may interfere with thyroid hormone medication used to treat hypothyroidism. In one randomized double-blinded trial, 60 patients with a mild form of hypothyroidism called subclinical hypothyroidism were given low or high-dose phytoestrogen supplements both also contained 30 grams of soy protein , the amount that might be obtained from a vegetarian diet.

The authors suggested that female vegetarian patients with subclinical hypothyroidism may need more careful monitoring of thyroid function. However, the authors also found a benefit on of reduced cardiovascular risk factors in the high phytoestrogen group, with a significant reduction in insulin resistance, inflammatory markers, and blood pressure. The effect of soy on thyroid function needs further examination. The contents of this website are for educational purposes and are not intended to offer personal medical advice.

You should seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website. The Nutrition Source does not recommend or endorse any products. Skip to content The Nutrition Source. Harvard T. The Nutrition Source Menu. Search for:. The Takeaway: Soy is a unique food that is widely studied for its estrogenic and anti-estrogenic effects on the body.

Studies may seem to present conflicting conclusions about soy, but this is largely due to the wide variation in how soy is studied.

Results of recent population studies suggest that soy has either a beneficial or neutral effect on various health conditions. Soy is a nutrient-dense source of protein that can safely be consumed several times a week, and is likely to provide health benefits—especially when eaten as an alternative to red and processed meat. Heart Disease Soy protein took center stage after research showed that it might lower levels of harmful cholesterol.

The authors explain that soy is likely to be safe. However, consuming excessive amounts may create health risks in some people, such as those with undiagnosed hypothyroidism.

There are many concerns around the health impacts and environmental safety of genetically modified crops. In one review, researchers suggest that eating GMOs could lead to illnesses that are resistant to antibiotics. Its authors also questioned the long term safety of GMOs, as they are a relatively recent development. Also, the amount of potentially beneficial isoflavones may be lower in genetically modified soybeans.

The transfer of allergens and the formation of new allergens are additional risks of GMOs. Moderate amounts of whole soy foods included as part of a varied and healthful diet may offer health benefits. Soy isoflavone supplements in particular can also help reduce the risk of hormone associated cancers and osteoporosis in women, as well as type 2 diabetes in both men and women. More research is necessary on both organic and genetically modified soy to assess their overall benefits and risks.

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This article looks at the causes of postprandial somnolence, or food coma, and explains how people who often feel sleepy after eating can cope with…. Hot water bottles can help to relieve aches and pains. Learn more here. What to know about soy. Medically reviewed by Natalie Olsen, R. Types and uses. Share on Pinterest Soybeans can play a role in a variety of meals and supplements. Share on Pinterest Soy is an important protein for many vegetarians and vegans. Share on Pinterest Genetically modified foods could potentially lead to illnesses that are resistant to antibiotics.

Latest news Scientists identify new cause of vascular injury in type 2 diabetes. Adolescent depression: Could school screening help? Related Coverage. Given the right conditions, these compounds copy the action of the female hormone oestrogen but are much less powerful — about 1, times less. There are many types of phytoestrogens, one example being isoflavones. Isoflavones are very strong antioxidants and can mimic the effects of oestrogen, but their full physiological effects are still being investigated.

Soybeans are the most common source of isoflavones in food. However, the amount of isoflavones varies with the type of soy food, preparation method and brand. Some of the richest sources of isoflavones are soy flour and soy nuts. Having a diet rich in soy foods is linked with a lower risk of cardiovascular disease , including stroke and coronary heart disease. Oestrogen may protect women against heart disease during their reproductive years, but rates of heart disease increase after menopause.

Soybeans have been shown to lower total cholesterol and LDL cholesterol levels, both known risk factors of heart disease. An analysis of clinical trials suggests 14g to 50g of soy protein can significantly reduce total blood cholesterol levels, LDL bad cholesterol levels and triglycerides, while moderately increasing HDL good cholesterol levels. Whole soy products such as soymilk, soybeans and soy nuts have a greater effect on improving cholesterol levels than processed soy products. It is not known how this happens — it could be phytoestrogens or soy proteins working alone or together.

Another reason could be, the amount of animal protein in the diet including saturated fat and cholesterol within the animal protein may be reduced and indirectly improve our blood cholesterol levels. However, studies also show that eating soy protein without isoflavones results in only small cholesterol reductions, and isoflavone supplements alone have minimal cholesterol lowering effects.

Due to their phytoestrogen content, it is thought soy can reduce menopausal symptoms such as hot flushes. This is based on observations of women in some parts of Asia, who tend to have soy-rich diets and typically fewer hot flushes during menopause than women on meat-rich diets. The phytoestrogens in soy appear to act like a mild form of hormone replacement therapy HRT. However, compared with traditional HRT, it would take almost a year of regular soy consumption to have similar health benefits.

More research is needed, but soybeans may help some women to manage menopausal hot flushes, even if only modestly. Do not take highly processed soy supplements if you have a high risk of breast cancer, or are a breast cancer survivor.

Eating moderate amounts of whole soy foods appears to be healthy. Generally, around 30 to 50mg of isoflavones is enough to offer health benefits. Examples of the average isoflavone content of some foods include:. Although there has been concern that high consumption of soy for some men and people with thyroid conditions may be risky, research suggests this is not the case.

Studies have also shown the use of soy infant formula in healthy, full-term babies does not appear to be harmful. However, infant soy formula may be harmful to premature babies and is best avoided. Check with your maternal and child health nurse or doctor.

Some people do not wish to eat genetically modified GM foods. Soy products imported from the United States are the main source of GM ingredients in food sold in Australia. Some soybean crops have been genetically modified to be resistant to herbicide, but they are otherwise identical to non-GM soybeans.

Genetically modified soy is found in primary soy products such as tofu or soy flour , but it can also be found in a wide range of other foods such as chocolates, potato chips, margarine, mayonnaise, biscuits and bread. Soy allergy can occur in some people due to a reaction to soy protein causing the immune system to react abnormally.