Plant-based milk alternatives like soy milk have exploded in popularity in recent years. But how does soy milk stack up against traditional dairy milk when it comes to nutrition and health impacts? Read on as we dive into the pros and cons of each.
The Nutritional Breakdown
When it comes to vitamins and minerals, soy milk provides higher amounts of some key nutrients, while dairy milk provides higher amounts of others.
Soy milk naturally contains more:
- Fiber
- Vitamin E
- Vitamin K
- Iron
- Potassium
- Magnesium
Cow’s milk naturally contains more:
- Protein
- Vitamin A
- Vitamin B12
- Riboflavin
- Phosphorus
- Zinc
Both provide a good dose of key nutrients like calcium, vitamin D and vitamin B3/niacin. Fortified versions help boost levels of nutrients that each lacks naturally.
When it comes to calories and fat, it can vary greatly depending on the product. Low-fat cow’s milk packs around 100 calories and 2.5g fat per cup while full-fat varieties deliver 150 calories and 8g fat. Soy milk ranges from 80 to 140 calories and 4 to 5g fat per cup depending on whether you choose low-fat, regular or high-protein blends.
The clear winner is tough to call nutritionally since each milk replacement has its own strengths and weaknesses in the vitamin and mineral department. But for the nutrients that matter most – like calcium, vitamin D and protein for bone health – both can deliver when opting for fortified kinds.
Protein Power
Dairy milk beats out soy when it comes to protein, with around 8 grams per cup compared to soy’s 6 to 7 grams. However, soy still offers decent protein, especially varieties specially formulated for higher protein content. Unlike the complete proteins in animal products, soy contains plant-based proteins which are incomplete on their own.
However, pairing soy with grains like rice or wheat can provide all the essential amino acids our body requires from proteins. Those following plant-based diets simply need to mix up protein sources to ensure they meet needs rather than depending solely on soy.
Those who are more active or need a higher protein intake would benefit more from cow’s milk and its muscle-supporting abilities. But soy can still play a valuable role in many fitness lover’s diets.
Beneficial Bioactive Compounds
Here’s an area where soy really shines. It contains unique compounds called isoflavones, including daidzein and genistein. These act as phytoestrogens with weak estrogen-like effects in the body. For those going through menopause, they may relieve hot flashes and support heart health. Evidence also suggests these soy isoflavones lower LDL “bad” cholesterol levels.
In addition to the isoflavones, soy contains various bioactive compounds linked to benefits like improved blood pressure, oxidative stress reduction and anti-inflammatory effects. While cow’s milk doesn’t boast the same riches when it comes to valuable plant compounds, both provide sources for antioxidants like vitamin E.
Health Concerns
Some people run into issues when consuming soy or dairy. Soy can trigger food sensitivity or allergic reactions, but compared to cow’s milk it results in less occurrences of food-related allergic disorders. Lactose intolerance is also more widespread than soy intolerance.
Those with thyroid issues need to be mindful of overdoing soy intake. The isoflavones may suppress thyroid function, especially for those already taking medication for hypothyroidism. But for healthy individuals, moderate soy consumption appears to cause little to no adverse effects on thyroid function.
Milk isn’t without it’s own considerations either. Besides needing to watch for allergy or intolerance triggers, some argue we aren’t designed to digest dairy past infancy with rates of lactose intolerance reaching almost 70% in some populations. There’s also the ethical considerations surrounding dairy production practices.
As with most things, moderation and avoiding overconsumption reduces risk of adverse health outcomes. Those with specific health conditions would be wise to consult their healthcare provider about whether cow dairy or soy products are suitable dietary additions.
The Verdict
When weighing all the nutritional pros and cons, soy milk gives cow’s milk good competition. Calcium and vitamin D fortified soy milk can promote just as strong bones and teeth. Both offer their own sets of pluses and minuses when evaluating vitamins, minerals, protein quality and bioactive health compounds.
Those who require higher protein intakes or follow diets like paleo eliminating all legumes may want to stick with dairy milk. Vegans or plant-based dieters, those avoiding dairy for health issues, or people wanting soy’s unique phytochemical benefits will likely preference soy-based beverages.
As with most dietary decisions, balance and moderation tends to win out over dogmatic adherence to one “best” food. Soy and dairy can both play a role in a well-rounded diet (unless eliminating for personal reasons). Alternating between or mixing both milk substitutes may allow people to reap their own potential upsides.