By Maryann Tomovich Jacobsen, MS, RD
Last November, I defended my choice of drinking skim milk after it got some bad press. Now I feel the need to defend milk as a whole.
While there has always been controversy about whether or not people need to drink milk, this has been taken to new heights. A petition filed on July 19th from The Physicians Committee for Responsible Medicine (PCRM) asks the government to amend the National School Lunch Act to exclude dairy milk as a required food for school lunch. According to a press release on PCRM’s website, here’s why:
“The promotion of milk ingestion in children is, in effect, the promotion of an ineffective placebo,” the petition states. It mentions that other products like calcium-enriched soymilk and rice milk contain calcium without sodium and animal protein (found in milk) that cause calcium to be excreted from the body. The report also mentions the high rates of lactose intolerance and milk allergies.
From this report, it sounds like the calcium in milk is less effective than calcium from other sources. So, I did some digging…
Gathering the Evidence
I started with a research study that helped fueled this fire. In a 2012 study published in Archives of Pediatric and Adolescent Medicine, researchers examined dairy, calcium, and vitamin D intakes in 6712 girls aged 9 to 15 years. During the seven years follow-up, 3.9% of the girls developed a stress fracture. Dairy and calcium intakes had no impact on stress fractures but vitamin D did — and was inversely related to the risk.
This doesn’t surprise me. Vitamin D is needed for calcium to be deposited into bone — and the small percentage of girls who got a stress fracture were more likely to have low vitamin D intakes.
As far as the animal protein question, a 2009 controlled feeding study published in the American Journal of Clinical Nutrition put this theory to the test. Twenty seven postmenopausal women had an increase in dietary (meat) protein, from 10% to 20% of energy. There was a slight improvement in calcium absorption in the higher protein group, which compensated for the slight increase in urinary calcium excretion.
As for sodium, most fluid milk contains less than 140mg, meeting the criteria for a low-sodium food. Additionally, most people drink milk as part of a total diet that is either high, moderate, or low in sodium.
“There is an overwhelming body of literature that shows dairy has a positive effect on growth and bone health of children,” say Connie Weaver, PhD, head and distinguished professor of nutrition science at Purdue University who specializes in calcium metabolism and bone health. “In many countries where milk isn’t available, you see poor growth.”
Weaver has recently been commissioned to put together a report on the benefit of dairy for the World Health Organization, Food and Agriculture Organization of the United Nations. She hopes to bring science front and center to the debate.
“The absorbability is pretty much equivalent,” she says, when asked about differences in calcium absorption in different foods. “The deal is, milk provides a whole package of nutrients, including protein, potassium, vitamin D, riboflavin, magnesium, and vitamin B12.
She also explains that any increases in calcium excretion from dairy protein is offset by increases in absorption. She mentions that phytates and oxylates in certain vegetables like spinach, rhubarb, and dry beans can decrease calcium absorption. But she says the biggest barrier to calcium utilization is sodium.
“In Asia where sodium intakes are high and calcium low, fracture rates are on the rise and will comprise over half of the world’s fractures by 2050,” she says. “The goal is to increase calcium intakes and lower sodium.”
In Weaver’s opinion “the amount of calcium counts” and dairy products are a very rich source (about 300mg per dairy serving) and it’s not practical to get it all from vegetables. She also recommends treating vitamin D separately because drinking milk doesn’t guarantee people will meet their requirements.
“The only group I have found that gets enough vitamin D from diet is Scandinavians who consume plenty of oily fish,” she says. Even if someone drinks three glasses of milk a day, they are getting only half (300IU) of what is recommended for people age 1 to 70 (600IU).
Nobody has to drink milk, but it is a convenient and absorbable source of calcium and vitamin D. People who are lactose intolerant, allergic to milk, or vegan can choose from an array of fortified non-dairy beverages. Those who want to avoid dairy and nondairy beverages need to be vigilant about checking the amount in the foods they eat.
And with a recent trial finding that that more than one-third of children are falling short on calcium and vitamin D intake, I don’t think taking milk off school lunch requirements makes sense.
Instead of debating whether or not people should drink milk, I think it’s more beneficial to provide the public with the latest research and sources of calcium so they can decide for themselves. And then we need to respect individual decisions.
Where do you stand on the milk debate? Share your thoughts in the comments section below.