With the influx of so many new kinds of soy foods to
the market today, from soup to nuts, choosing which ones to add to our diets can
be confusing. And with so much soy hidden in not-so-healthy foods we sometimes like
to eat — like doughnuts! — it seems impossible to keep track of the
coming and going of the soy we’re eating. Some may wonder if including soy
foods is worth the bother, or if they should even avoid them. In this article, we
hope to give you some answers about the nutritional qualities and health benefits
We want you to known that soy foods have gotten mixed reviews over the years. But
frankly, we have often wondered where the intense feelings and emotional fervor
about this humble green bean come from!
Many patients are looking for alternatives to hormone replacement and are curious
about soy foods, soy supplements, soy isolates and phytoestrogens, but don’t
know where to start. Although soy may not be helpful for all women in this regard,
we have found that adding soy can provide health benefits during perimenopause and
Soy as a food
As we walk the aisles of our grocery stores, health food stores and farmer’s
markets, faced with a choice between traditional and nontraditional soy foods, we
may wonder where the best soy can be found. We know from historical accounts that
soybean curd (tofu) was used in China by all ranks of society, from peasants to
royalty, as a household staple. For 5000 years it has been considered one of the
five sacred plants — the others being rice, wheat, barley and millet. We know
that soy is high in nutritional value as a non-animal source of eight of the essential
amino acids, which makes it the only complete plant protein. Whole soy foods also
are a good source of fiber, B vitamins, calcium, and omega-3 fatty acids.
Soy foods come in all shapes and sizes
For those of you inclined to experiment in the kitchen, opportunities abound to
add soy protein to your diet.
Edamame is the Japanese name given to the small, green (not quite
mature) soybean. Most often found in the frozen food section, shelled or unshelled,
edamame can be boiled, steamed or eaten raw as a snack. With a sweet taste similar
to green peas or artichokes, edamame can be served as a hot side dish like peas
or corn, or used in soups, salads and stir-fries.
Tofu is made from soymilk that is curdled with mineral salts. The
liquid is drained and the remaining curd pressed into a custard-like cake. Tofu
comes in many varieties, from extra-firm to silken soft. Its texture may take some
getting used to, but tofu is a very versatile food that absorbs the taste of the
ingredients mixed with it. Tofu can be used in casseroles, stir-fries, and egg dishes,
and adds good plant protein. We know women who add tofu to anything and everything
— from cereals, cottage cheese, scrambled eggs, and spaghetti, to kebabs,
fruit dishes and puddings. Many supermarkets are now selling marinated tofu that
has a denser, more flavorful consistency that many people prefer. Tofu can also
be substituted for cream cheese in dips, bagel toppings or other recipes.
Soy milk doesn’t come from a soy cow, but is processed from
the bean itself. Different manufacturing processes produce soy milk with varying
levels of protein and fat — the greater the protein content (generally at
least 4%) the higher the isoflavone content. Fat content usually ranges from 1–3%.
All soy milk is lactose- and cholesterol-free. Most soy milk is now fortified with
calcium, vitamin D and other nutrients, and many flavors are available. Soymilk
can be packaged in aseptic cartons with a shelf life of a year or kept refrigerated
like cow’s milk. Plain soy milk powder can be used for baking, but unless
it has been sweetened does not usually make a very palatable drink.
Soy cheese is made from tofu and loses much of its nutritious value
in processing, but is nonetheless a good non-dairy alternative.
Tempeh is an Indonesian soybean product that has been inoculated
with a mold then incubated. It may sound gross, but tempeh is one of our favorite
fermented soy foods. In America, tempeh is usually sold refrigerated or frozen and
often used as a meat or poultry substitute. It can be marinated, baked, grilled
Miso is a Japanese fermented soybean and grain paste that is used
as a soup base, similar to bouillon cubes but without the nasty food additives.
Miso is salty, but again very nutritious and valued for its digestive properties.
Soy flour is ground from whole or shelled soybeans into a fine
powder, and is best kept refrigerated to retain freshness. Soy flour can be used
for thickening and in baking, but because it contains more moisture and is gluten-free
it does not produce equivalent results, so some modifications have to be made when
substituting it for wheat or other flours.
Soy nuts are shelled soybeans that have been dried and roasted
until crunchy. Soy nuts are lower in fat than other snack nuts and are sold salted
or spice-flavored — even candied.
Soy protein isolate is soy protein processed from defatted soy
flakes or soy powder. The powder is 90% pure protein, very bland and highly digestible.
Soy protein isolates are easily added to shakes, smoothies and other recipes to
make a creamy texture. Plain or flavored versions are available and can be kept
Textured soy protein is a processed form of soy flour and water,
which is used primarily as a meat substitute in ground meat dishes, stews, and kebabs.
Textured soy protein is sold in granules or chunks, has less fat than tofu, and
should contain no other additives.
Soy sauce and tamari/shoyu are
fermented soy products that lend a richer flavor to many Asian recipes. The label
should state that it contains only soybeans, salt, water and sometimes wheat —
no hydrolyzed vegetable protein (HVP) or caramel coloring. “Lite” refers
to lower salt content.
Soy researcher Mark Messina notes that around 30% of women between the ages of 20
and 69, and 40% of women over the age of 70 are getting less than the recommended
dietary allowance for protein. Soy foods provide high-quality protein and are low
in saturated fat. He also notes that back in the early 1900’s, our diets consisted
of somewhere around 70% plant protein and 30% animal protein. Today, it’s
more like 50:50. Since soybeans are 38% protein, which is very high for a bean ,
they make a great choice for women who want to increase the quality protein in their
diet — specifically plant proteins.
Soy has been the protein of choice for many vegetarians and nutritionists for many
years. Cookbooks from the Moosewood Restaurant, among other vegetarian cookbooks,
abound with soy recipes, and many people of all ethnicities enjoy soy as a regular
part of their diet with seemingly little to no ill effect. From the China Study
to the Okinawa Plan, more and more people are waking up to the power of the plant-based
Asian diet in improving health and longevity.
Soy isoflavones — whole beans are best
Isoflavones are one branch of a family of chemical compounds, called phytochemicals,
found in all plants and legumes, including beans, green leafy vegetables, yellow
and orange vegetables and whole grains. A diet rich in a range of phyto-
(Greek for plant) chemicals is the foundation of a healthy complete diet.
For you to glean the best from the vast fields of soy grown in this country, always
look for labels that say “Non-GMO.” It is quite possible that the pesticides used
on soy (beans that are eaten directly or eaten by livestock) may bioaccumulate in
our tissue and cause problems. But this is not a soy-isolated problem, which is
why we also eat organic where practicable. Soy is a cash-making crop in the US,
and some varieties have been genetically modified to increase yields. Scientific
data is conflicting on the long-term health effects of eating genetically-modified
foods, but it is our preference to avoid them whenever possible.
While still controversial in some circles, we’ve studied the scientific literature
on isoflavones in some depth, and feel confident that their health benefits outweigh
any hypothetical harm they could cause — unless you have a
Soy: How much am I already getting, how much should I add?
Calculating healthy daily serving sizes, grams of proteins, and milligrams of soy
isoflavones may be a bit mind-boggling. But you don’t need a math degree if
you remember that for the cardiac benefits of soy, you need two to four servings
a day to get the suggested 25 grams of protein. One serving (see chart) is equivalent
to a cup of soymilk, a half-cup of tofu (about one-third of a block), or one-quarter
cup of soy nuts.
While many women are looking to add soy foods to their diets, others wonder how
much hidden soy there is in our foods. It’s true the US is the world’s
second-largest grower of soybeans, and soy is turning up everywhere in our industrial
food chain, from store-bought packaged goods to fast foods, bakery items to livestock
feed. So it surprised us to learn how in 2000, the Californian women in one study
were getting as much as one-fifth of their total soy isoflavones from doughnuts!
Despite soy’s wide availability, most people here in the West still eat relatively
very little of it: only 0.15 to 3.0 mg/day of isoflavones, according to some reports.
There is also a lot of soy oil being used in fried foods, snacks and commercial
salad dressings. We wish we could say that was a good thing, but let us explain
why it probably is not. Even though soybean oil is a polyunsaturated fat, we don’t
recommend eating a lot of it, and don’t consider it a healthy cooking or salad
oil because it contains more of the types of fatty acids that most of us get too
much of. Unfortunately, this favors inflammatory processes in our cells .
Despite the many delicious soy foods around (over 1,600 food products are available
in the US alone), it may be difficult for you to get the 80 mg per day of soy isoflavones
— the amount considered helpful for hormonal imbalance — from your diet
alone. Or you may not like the taste or texture of soy. In this case, you may want
to investigate other sources of soy including soy supplements and functional foods.
We’ve found that soy shake made with whole, non-GMO soybeans are often useful.
Talk to your practitioner about her or his recommendations. Soy protein shakes and
bars taste good and can be an easy way to boost your daily intake.
Only part of the story
As long as people continue to eat and enjoy soy products, the key, as with everything
we recommend, is balance. While it is entirely possible that there are people out
there who reap tremendous health benefits from soy, there are others who may not
— the majority, however, just need to look East to see that a varied diet
that contains some quality soy is fine.
First and foremost to listen to your body. If you do well with soy products, chances
are you are metabolizing and tolerating them effectively. If you react negatively
to soy, you can try digestive enzymes and a probiotic supplement, you can try a
detox diet, or you can avoid it. As in all things, practice being an informed consumer
when purchasing soy products, and do so in moderation. Eat a varied and nutritious
diet, filled with lots of fruits and vegetables, minimally processed foods, and
healthy fats — and, of course, a little chocolate now and then.
Don’t think of soy as an additive to one’s diet (it does contain calories).
And don’t think of it as a magic cure-all or easy treatment for all health
woes — remember, even in the natural world there is no magic bullet. Soy is
a great food and can be effective in supplemental form, as well, but only as a part
of a much larger and robust whole. Get to know yourself, get to know soy, talk to
your practitioner and then trust yourself to make the right decision for you.
Balk, E., et al. 2005. Effects of soy on health outcomes. Evidence Report/Technology
Assessmenet No. 126. (Prepared by Tufts–New England Medical Center Evidence–based
Practice Center under Contract No. 290-02-0022.) AHRQ Publication No. 05-E024-2.
Rockville, MD: Agency for Healthcare Research and Quality. URL: http://www.ahrq.gov/downloads/pub/evidence/pdf/soyeffects/soy.pdf
Barnes, S. 2004. Soy isoflavones — phytoestrogen and what else? J. Nutr.,
134 (5), 1225S–1228S. URL: http://jn.nutrition.org/cgi/content/full/134/5/1225S
Henckel, J. 2000. Health claims for soy protein; questions about other components.
FDA Consumer Magazine. URL: http://www.fda.gov/fdac/features/2000/300_soy.html
(accessed 01.31.2006). [This is a good summary of the FDA health claim.]
Klemola, T., et al. 2002. Allergy to soy formula and to extensively hydrolyzed whey
formula with cow's milk allergy: A prospective, randomized study with a follow-up
to the age of 2 years. J. Pediatr., 140 (2), 219–224.
Sacks, F., et al. 2006. Soy protein, isoflavones, and cardiovascular health. An
American Heart Association Science Advisory for professionals from the Nutrition
Committee. Circulation. Published online before print, 01.17.06. URL: http://circ.ahajournals.org/cgi/content/abstract/
CIRCULATIONAHA.106.171052v1 (accessed 01.31.2006).
Casini, M, et al. 2006. Psychological assessment of the effects of treatment with
phytoestrogens on postmenopausal women: A randomized, double-blind, crossover, placebo-controlled
study. Fertil. Steril., 85 (4), 972-978.
Daniel, K. 2005. The Whole Soy Story. Winona Lake, IN: New Trends Publishing,
Jacobi, D. 2001. Amazing Soy: A Complete Guide to Buying and Cooking This Nutritional
Powerhouse with 240 Recipes. NY: Morrow Cookbooks.
Messina, M., & V. Messina. 1994. The Simple Soybean and Your Health.
Wayne, NJ: Avery Publishing Group.
Oser, M. 1996. The Soy of Cooking: Easy-to-Make Vegetarian, Low-Fat, Fat-Free, and
Antioxidant-Rich Gourmet Recipes. Hoboken, NJ: Wiley.
Cancer Nutrition Info’s site has a good list of references. URL: http://www.cancernutritioninfo.com
Revival Soy’s benefits & research page: http://www.revivalsoy.com/whysoy/