A study published in the scientific journal Nutrition Research last November looked at the effects on nutrient intake when dairy foods are reduced or removed from the diet. Rather than focusing just on calcium—which is easily found in other foods—the researchers looked at several nutrients that are abundant in dairy products. They concluded that even when “calcium-replacement foods” provided the same amounts of calcium as dairy products, they fell short on other nutrients that milk provides.
This study was funded by the National Dairy Council and administered by the Dairy Research Institute. Two of the researchers work for the Dairy Research Institute. I don’t generally get too excited about sources of funding for nutrition research because they don’t affect the findings. They can affect how those findings are interpreted, though. Needless to say, I have a pretty different perspective from these researchers. But even so, I feel confident that the data fall in favor of plant sources of calcium.
Using both the USDA’s MyPyramid (the research was done before the release of MyPlate), and data from the NHANES study (a national survey of food intake), the researchers looked at what happens when you replace a serving of a dairy “composite” (a mixed serving of milk, cheese and other dairy foods) with a nondairy “composite” that provides an equivalent amount of calcium. The nondairy composite consisted of 71% fortified orange juice, 18% fortified soy milk, 10.5% leafy greens, and 0.5% fish with bones, reflecting average contribution of these foods to American diets.
So what happens when you replace dairy with this assortment of foods? Intake of protein, certain B-vitamins, phosphorus, and zinc drop. However, all were still high enough to meet the RDAs, with the exception of zinc which was marginally low. (Vitamin D was low in both the dairy-rich and dairy-free diets.)
Here are some other things that happened when dairy products were replaced with nondairy foods. The amount of saturated fat and sodium both dropped. And the amounts of vitamin A, potassium, and magnesium all increased. The study didn’t analyze vitamin C, vitamin K, iron or fiber, none of which are found in dairy products and all of which would be provided by the nondairy composite.
So we can flip this around and look at the effects of replacing plant sources of calcium with dairy foods: Doing so causes a drop in fiber, vitamins A, C, and K, and in the minerals potassium, magnesium and iron. Vitamins C and K, and potassium and magnesium are all important for bone health, by the way.
Had the study been done in lacto-ovo vegetarians it would have shown that those who remove dairy foods from their diet need to identify good sources of zinc and vitamin B12. But we know that, and we all—hopefully—make sure we are finding other ways to include these nutrients in our diets.
This research confirms that milk and other dairy products have nothing to offer that you can’t get elsewhere. And so there is never any reason to participate in the suffering that lies behind milk production.
Reference: Fulgoni VL, 3rd, Keast DR, Auestad N, Quann EE. Nutrients from dairy foods are difficult to replace in diets of Americans: food pattern modeling and an analyses of the National Health and Nutrition Examination Survey 2003-2006. Nutr Res 2011;31:759-65.