Is Soy Milk Good for You?
Choosing a Soy Beverage that is Healthy and Tastes Great
With an ever-widening array of soy-based beverages - and knowledge of health benefits that go with it - more and more are turning to dairy alternatives.
Why drink soy milk?
- Allergies
- It is estimated that 1% to 3% of the population is allergic to cow’s milk (Bahna, 2002). An allergic response is immune in nature; it occurs when the body recognizes milk proteins as foreign invaders, and therefore a threat. The allergic response is a sign the body is trying to “fight off” these invaders.
- Lactose Intolerance
- Lactose intolerance encompasses many disorders of digestion and metabolism associated with the sugar – lactose – prevalent in milk. The enzyme needed to break down lactose in the body is called lactase. Presence of this enzyme is highest in infants and children, and tends to taper off as people age. Worldwide, most adults are lactase deficient and therefore lactose intolerant.
- Vegan
- Most soy milks are vegan; however, some flavoured beverages might contain milk-derived ingredients. Always check the label.
- Vitamin D: Vitamin D3 as cholecalciferol is derived from sheep's wool; look for the plant-derived Vitamin D2 as ergocalciferol.
- Nutrition
- Soy beverages are high in complete protein, calcium, and other nutrients. Generally, there are between 6 and 8 grams of protein per cup of soy milk, compared to 8.1 grams for one cup of 2% cow's milk.
- Functional food
- The Food and Drug Administration in the United States allows a health claim for soy protein: "25 grams of soy protein a day, as part of a diet low in saturated fat and cholesterol, may reduce the risk of heart disease."
- There is some evidence that soy isoflavones decrease hot flashes associated with menopause.
Nutritional Considerations when Choosing a Soy Beverage
1. Natural vs. Not
For those who prefer a natural approach, there are several brands of unsweetened, natural soy beverages available. These recipes are not fortified with calcium or anything else (see below) and usually include simply water and soy beans. While soy beginners might find the taste a touch sour, learning to like it might be worth it: natural soy milks are not diluted with other fillers like sugar and thickeners, meaning more soy actually ends up in your cup. This translates to higher isoflavone levels (likely responsible for health benefits) and up to a whopping 12 grams of protein per cup. Alternatively, natural soy milk can be made at home.
2. Fortification
The correct name for soy “milk” is actually soy “beverage”. While they are most often used in place of, or interchangeably with, dairy milk, soy-based beverages are actually very difficult from cow’s milk when it comes to composition.
Most soy beverages are fortified with calcium in the form of calcium phosphate or calcium carbonate. Soy beverages have been under recent scrutiny for containing calcium that is not as bioavailable as dairy milk; it seems this is true for beverages using tricalcium phosphate (Zhao al. 2005). Beverages fortified with calcium carbonate, however, have been shown to be just as bioavailable (bioavailability is the extent to which the body can use a dietary source) as the calcium from cow’s milk (Zhao al. 2005).
Up to about 500 mg calcium (approximately the amount in 2 cups cow’s or soy milk) can be absorbed at one time.
Most soy beverages are fortified to provide similar nutritional content to dairy milk, meaning added B-vitamins (especially B12, which generally occurs only in meat, dairy, and eggs), Vitamin D , zinc, and Vitamin A.
Unlike cow’s milk, soy beverages also contain iron. Though amounts vary between brands, it is usually around 1.8 mg per cup, or 10% of the recommended daily allowance.
Several mainstream soy beverages have recently been launched that include unconventional additives such as fibre and the omega-3 fat DHA, derived from seaweed.
3. Healthy Fats
Many soy beverages contain considerable amounts of heart-healthy omega-3 fats. While low-fat versions are available, most of the fat in soy beans is polyunsaturated (including some omega-3s) so it is not necessarily preferable to purchase a lower-fat variety.
4. Flavours
Soy beverages are available in a multitude of delicious flavours, from vanilla to plain to cappuccino.
5. Versatility
Soy beverages can be used like cow’s milk; except when mixed with acidic liquids like coffee, where it tends to curdle. It is still fine to eat, but might not taste (or feel) the same. Try:
- Smoothies
- Soups (do not boil)
- Hot chocolate
- Cereal
- On their own
- Mixed with a little bit of flax oil for a nutritional boost
- In slightly cooled tea or coffee
- In puddings and desserts
The Bottom Line
- Soy milk (beverage) can substitute for dairy milk in most recipes
- Fortified varieties provide similar nutrients to dairy milk, including vitamin D.
- Soy beverages provide more iron and polyunsaturated fats than dairy milk
- Soy protein contains beneficial isoflavones
Tip: Thinking about trying soy milk? Try several brands before giving up. They vary considerably in texture, taste, and sweetness.
References:
Bahna SL. Cow's milk allergy versus cow milk intolerance. Ann Allergy Asthma Immunol. 2002; 89(6 Suppl 1):56-60.
Zhao Y, Martin BR, Weaver CM. Calcium bioavailability of calcium carbonate fortified soymilk is equivalent to cow's milk in young women. J Nutr. 2005 Oct;135(10):2379-82. Available from: http://www.ncbi.nlm.nih.gov/
