Articles and Topics
Soy versus Dairy
We recently received an e-mail from a reader who expressed concern that we’re over-promoting the use of dairy products, specifically milk, in our advice on nutrition and pediatrics. I took this reader’s concerns seriously and agree that we need to fully educate our parents about the benefits—and risks—of both soy and dairy products. It’s also important to consider the needs of parents who wish to practice a vegetarian diet and help all our parents arm themselves with “evidence-based” information, instead of opinions, as they tend to their families’ nutritional needs.

As a registered dietitian with many years’ experience, I have kept myself informed about the pros and cons of soy-based and dairy-based diet choices, and I take this information into careful consideration when making dietary recommendations. I am, in fact, a proponent of lacto-ovo vegetarian diets, particularly as we see more health issues arising from the overuse of high-fat convenience foods and poor nutritional choices made by many families. That being said, I will try to address what I feel are some of the controversies surrounding the soy-dairy issue.

Each year more information is released to the public regarding issues on certain foods, nutrients and medications. There are so many articles that it’s especially difficult to keep up with what is being recommended.

Vegetarian diets have become more popular due to the increased knowledge of food and how it fuels the human body. The most common vegetarian diets are lacto-ovo and vegan. Lacto-ovo diets are high in complex carbohydrates that do not allow meat but do allow for some animal-based products such as milk, cheese, eggs and fish. Vegan diets are strictly plant-based and do not include any animal-based products or fish. Vegans get their protein from dried peas and beans; a careful combination of plant and grain foods to provide the essential amino acids; and soy, which is a high-protein food.

Soy is the base protein in diets of most of the world’s people. It is cheap to grow, does not require an enormous amount of natural resources to produce and is easily available. Meat, on the other hand, is plentiful at an affordable price only in a limited number of countries, particularly the United States. Likewise, the United States is the largest producer of cow’s milk, so dairy products are plentiful and affordable in America and are, in fact, subsidized by the government.

Because of their availability, dairy-based products have always played a large part in American diets. Milk provides all of the necessary nutrient groups for human growth and development—protein, carbohydrate and fat—and provides calcium for bone and tooth growth. Vitamin D is added to milk to increase calcium absorption.

Soy products are naturally fat-free, making them a good option in planning a healthy, reduced-calorie diet. However, soy products—such as soymilk, cheese and ice cream—tend to be expensive and limited in availability.

It is important to understand that there are positives and negatives to most dietary choices. The reader who originally complained that we didn’t feature enough information about soy foods claimed that kids who drink cow’s milk are prone to obesity, earaches, diabetes, acne, bed-wetting and osteoporosis in adulthood. These claims do not have any scientific basis in fact. Obesity, for example, is caused by eating more calories than are used by the body. Earaches are usually bacterial infections in the inner ear and Eustachian tubes. Although there are concerns that cow’s milk can trigger diabetes in some people, the studies are still ongoing.

Many of these claims, which come from an anti-milk website, are based on opinions or older studies rather than evidence-based research. This is not to say that the pro-milk websites are innocent, either. When you investigate claims from any website, look for multiple scientific studies to back up the claims. Also, try to find out the purpose of the website. Is it purely informational or is trying to sell a product or book? Does it give you both sides with factual information to compare?

Back to the discussion about soy versus dairy. It is true that some individuals have sensitivities or allergies to cow’s milk. Lactose intolerance, or the ability to digest the milk sugar lactose, is common in many cultures and can cause very uncomfortable intestinal problems. Some individuals may be able to tolerate cheese, yogurt and ice cream because they’re processed to make the milk into a different product. Lactose intolerance is caused by a lack of lactase enzyme in the intestine but can be corrected with lactase drops or tablets taken orally before consuming. Allergies are more often triggered by the cow protein found in dairy products and can be very serious.

Likewise, many people also suffer from legume allergies and sensitivities. We are all aware of peanut allergies in children; even though soy is different, it is also in the legume family. Understandably, in families where a nut allergy is a problem, we are hesitant to recommend soy as an alternative food source.

Less than a decade ago, the USDA and National Institutes of Health (NIH) issued a statement that soy products appeared to be safe. However, as of this writing, the NIH has called for more investigation into the potential long-term effects of soy foods on infants and children, specifically about the effects of the phytoestrogens (plant estrogen compounds) found in soy products. While they will likely be proven safe after the studies are conducted, most medical practitioners are a little cautious about promoting soy over dairy products for very young children. It is also very important that infants and toddlers up to 2 years of age get an adequate amount of cholesterol in their diets for the development of myelin, a compound required for proper brain and nerve function. Cholesterol is only found in animal-based foods.