Monday, November 3, 2014

As Cow’s Milk Wanes in Popularity, Vitamin D Deficiency Rises

Up until recently, cow’s milk has been an integral part of the average child’s diet. It is often the drink of choice offered with meals and snacks. Packed with protein and vitamins, it’s no wonder it has been considered an essential part of a growing child’s diet.
According to research from the US Department of Agriculture, most Americans aren’t consuming enough dairy products. The Dietary Guidelines for Americans from 2010 recommends 2 cup-equivalents per day for children aged 2 to 3 years, 2.5 for those aged 4 to 8 years, and 3 for Americans older than age 8. However, per capita dairy consumption has long held steady at about 1.5 cup-equivalents, despite rising cheese consumption.

In terms of long term trends, interestingly, the USDA has found that per capita consumption of fluid milk is declining in high-income countries while growing in developing countries.

Fortified milk is an important source of vitamin D for children. However, parents in developed countries have been choosing in increasing numbers to feed their children unfortified non-cow’s milk such as soy, rice, almond or oat milks since the turn of the millennium. Fears of milk allergy, lactose intolerance, growth hormones and antibiotics often used to treat dairy cows have been cited as reasons for turning away from feeding their children cow’s milk after weaning.

What does this cultural shift mean for vitamin D levels in young children? A recent study published in the Canadian Medical Association Journal sought to find the answer.

Researchers tested the serum vitamin D levels of a group of 2831 children. The group included both cow’s milk and non-cow’s milk drinkers. Researchers looked at differences in blood levels of vitamin D associated with drinking cow's milk and non-cow's milk.

According to Dr. Jonathon Maguire, a pediatrician and researcher with St. Michael's Hospital who took part in the study:

 "Children drinking only non-cow's milk were more than twice as likely to be vitamin D deficient as children drinking only cow's milk. Among children who drank non-cow's milk, every additional cup of non-cow's milk was associated with a five per cent drop in vitamin D levels per month."

As western society moves away from the habit of drinking milk, these results are a cause for concern for the parents and the medical community. The key factors underlying proper vitamin D levels are either adequate milk intake or supplementation. We hope that this study will encourage parents and doctors to make sure to monitor vitamin D levels in children who avoid cow’s milk for various reasons.