Alternative Names soy, soy foods, phytochemicals , isoflavones, plant oestrogens
Definition Phytoestrogens are oestrogens contained in plants. They have a chemical structure similar to the human hormone oestrogen. They have a weak oestrogen effect when eaten. The most commonly studied are the isoflavones, found in soybeans and other legumes. The word soyfood refers to any food products made from soybeans. Soyfoods provide significant amounts of isoflavones.
What food source is the nutrient found in? Soy is found in numerous foods. Soyfoods include:
During menopause, women have fluctuations in oestrogen levels. These hormonal changes may increase the risk of heart disease and osteoporosis. These changes also cause hot flushes, night sweats, insomnia, and headaches. The ability of plant oestrogens to reduce these symptoms is now being studied.
Information In addition to the possible health benefits, soy foods are very nutritious. They are low in saturated fat, free of cholesterol, high in fibre, and rich in many vitamins and minerals. Soyfoods are high in protein.
Soy protein is the only plant protein that is considered complete. In fact, it is equivalent in quality to animal protein. Soy protein causes less calcium to be excreted from the body than animal protein does. This may protect kidney function. Soyfoods are also a good source of calcium, helping to protect the bones Soyfoods are also high in iron.
The benefits of adding phytoestrogens to the diet appear very promising. But researchers caution against adding large amounts. Too much of them may cause problems with development and fertility. No one suggests that they replace regular treatment for osteoporosis, heart disease, or high cholesterol. Plant oestrogens should be avoided by people who take certain medications. These include tamoxifen, which is used to treat breast cancer.
Soy protein helps to lower blood cholesterol. Scientists have known for nearly a century that the protein you eat helps determine your chances of having a heart and animal protein and not plant protein, induces arteriosclerosis.
Making soy foods part of a healthy diet can be easy, nutritious, and delicious. The following foods are excellent sources of isoflavones. They provide from 30 to 50 mg per serving:
roasted soy nuts (30 grams)
soy flour (1/2 cup)
soy grits (1/4 cup)
textured soy protein (1/2 cup, cooked)
soybeans (1/2 cup, cooked)
regular soymilk (1 cup)
tempeh (1/2 cup)
tofu (1/2 cup)
The only two soy products that do not contain isoflavones are soy oil and soy sauce.
Here are some tips for adding soy to a healthy diet:
Soy milk can be used instead of regular cow's milk.
Soymilk can be blended with a banana or other fruit to make a quick breakfast shake.
Tofu can be used in salads, soups, chili, stir-fries, or sauces. It can be a substitute for eggs, yoghurt, or meat. Tofu soaks up the flavour of whatever it is cooked with.
Soy yoghurt can be mixed with fresh fruit.
Textured vegetable protein (TVP) can be substituted for part or all of the beef in ground beef recipes.
Veggie burgers are great on the grill.
Roasted soynuts can be kept around as a crunchy snack. They can be sprinkled on cereal, yoghurt, or salads.
Soynut butter can take the place of peanut butter on bagels, bread, or English muffins.
Here's how to replace ingredients in favorite recipes with soy products:
1 cup dairy milk = 1 cup fortified soy milk
1 egg = 1 Tbsp. soy flour + 1 Tbsp. water or 2 oz. silken tofu
1 egg = 1/4 cup tofu (blend with liquid ingredients until smooth, then add to dry ingredients)
1 cup buttermilk = 1 cup soymilk + 1 Tbsp. vinegar
1 cup fruited yoghurt = 1 cup soft silken tofu + blended fruit
1 cup ricotta cheese = 1 cup firm tofu, mashed
replace 1/2 the cream in soup or sauces with silken tofu
replace 1/2 the cream cheese in cheesecakes with silken tofu
replace up to 1/4 of the flour in homemade breads with soy flour
replace up to 1/3 of the flour in muffins with soy flour
Author: Kimberly Tessmer, RD, LD Reviewer: HealthAnswers Australia Medical Review Panel Editor: Dr David Taylor, Chief Medical Officer HealthAnswers Australia Last Updated: 1/10/2001 Contributors Potential conflict of interest information for reviewers available on request
