Sarah-Jane Bedwell, SELF magazine
Everyone knows that milk is packed with calcium that builds strong bones (and helps you slim!), but are all milks created equally? There are lots of options and they are all very different. One pass through the dairy section of your local grocery store is enough to make anyone's head spin. What is soy milk? Does it have the same benefits as cow's milk? What about coconut milk? The list goes on and on! Let me help you sort it all out. Traditionally, milk is defined as "a fluid secreted by the mammary glands of females for the nourishment of their young," as is the case with cow's milk. However, milk can also be used to describe liquid resembling milk that is derived from a plant source, such as coconuts or soybeans. Plant-derived milk substitutes have gained popularity in recent years, leaving many consumers to wonder, "What are the nutritional differences between cow's milk and milk substitutes?" Let's look at the key nutrients.
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Calcium: Cow's milk in the human diet serves as a great source of calcium and protein. Just one serving of cow's milk provides 30% of your daily calcium needs and 8 grams of protein! Calcium occurs naturally in animal sources of milk, but must be added to milk substitutes during processing to improve their nutritional value. As a result, most milk substitutes have just as much, if not more, calcium than cow's milk. So almond, coconut, sunflower, or soymilk can provide a whopping 45% of your daily calcium needs, but keep in mind that it is added, not naturally-occurring.
Protein: If you're looking to get the same amount of protein as cow's milk has from these substitutes, you're out of luck. Coconut, sunflower, and almond milk contain only 1 gram of protein per serving. Soymilk seems to stack up the best against cow's milk, providing 6 grams of heart-healthy soy protein in one serving, but still falling short of the 8g of protein you get in one cup of milk.
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Vitamins and other nutrients: Other differences exist between cow's milk and plant-derived milks, but each seems to have its own unique benefits. For example, cow's milk is a source of various vitamins and minerals like potassium, phosphorous, and vitamin D. However, a single serving of almond or sunflower milk provides half your daily needs for vitamin E, an antioxidant that boosts the body's immune system. Sunflower milk also provides 60% of the daily value of phosphorus. Soy milk contains isoflavones and SELF's Breast Cancer Handbook warns, "soy foods (including soy milk) are rich in isoflavones, a type of estrogen that lessens the effects of your body's own estrogen. If you have a family history of breast cancer, talk to your doctor before adding soy to your diet. Women at higher risk must limit exposure to estrogen in many forms. (The type of estrogens in flax pose no risk.) Women who are trying to conceive, are pregnant or are breast-feeding should check in with their doctors check in with their first, too."
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Fat: With the exception of coconut milk, most plant-derived milk substitutes or low-fat cow's milk are low in saturated fat and contain no cholesterol, making them heart healthy options. They are also dairy and lactose-free, which is particularly beneficial for consumers with milk allergies or lactose-intolerance.
Since milk substitutes tend to be more expensive, they may not be suitable for everyone. Flavor differences may also be an important factor. Whatever your preference, just remember that nutritional value is the bottom line.
Special thanks to Vanderbilt Dietetic Interns Lauren Bradford and Jacquie Sullivan for their help with this post.