I recently gave a talk on childhood nutrition. My holistic approach is sometimes a bit unconventional, but it’s grounded in science. As a functional medicine physician, I’ve taken a special interest in nutrition. Beyond that, my experiences as a mother have pushed me to learn more. While much of the research presented here is directed toward children, these principles apply to adults as well.
I’m surprised by how much misinformation there is about nutrition, even among physicians and well-educated parents. Hopefully this helps to clear some things up.
In this 4 part series, I’ll address:
This week my focus is on the importance of calcium and vitamin D, and the myth that cow’s milk is the best way to get adequate amounts. It may shock you, but I don’t think that cow’s milk is a necessary (or even healthy) part of a child’s diet. My own daughter has never been offered milk on a regular basis. We transitioned straight from breastfeeding to water around age 2.
Children in the Unites States drink too much milk!
Dairy is a staple in most children’s lives. Although official World Health Organization (WHO) recommendations are to breastfeed until age 2 or longer, the general opinion and practice in the U.S. is to switch from formula or breastfeeding to cow’s milk at 12 months of life.
I find that many children don’t do well with dairy, as milk is one of the major contributors to food allergies and sensitivities. Beyond that, it is often offered in higher than recommended quantities, even among physicians. I informally polled a group of over 10,000 physician moms, and found that many of them were exceeding the recommendations for milk intake by the American Academy of Pediatrics (AAP).
We know that calcium is important for bone health.
Calcium is especially important during adolescence when bone building peaks between ages 12-15 years of age. Adequate calcium helps prevent osteoporosis. Calcium can also protect against lead toxicity by decreasing the absorption of lead in the gastrointestinal tract. It is also very important during pregnancy and breastfeeding, as adequate maternal levels protect a growing baby by preventing mobilization of lead stores from maternal bone.
However, two things are not certain.
First, it’s not clear if dairy products are the best source of calcium for most people. Despite aggressive marketing by the dairy industry, the verdict is still out as to whether or not milk really builds healthy bones.
Second, we don’t truly understand how much calcium we really need. Our current recommended intakes are based on short-term studies. Long-term studies are more relevant, but the few we have actually cast doubt on the need for high calcium intake that is currently recommended. Studies in other countries (India, Peru and Japan) where calcium intake is low do not show an increased rate of bone fractures, but other variables make this data hard to interpret. Read more from the Harvard School of Public Health.
The recommended calcium requirements depend on who you ask.
The recommended dietary allowance for calcium varies based on who you ask. The healthiest amounts have not yet been established.
The recommendations for calcium that are provided in the Dietary Reference Intakes (DRIs) developed by the Food and Nutrition Board (FNB) at the Institute of Medicine of the National Academies (formerly National Academy of Sciences) are:
The UCSF Medical Center has published the following recommendations:
The current recommendations for milk.
The AAP recommends 2 cups (16 oz) of milk or it’s equivalent for children ages 2-8. 16 oz of milk provides about 600 mg calcium and 200 IU Vit D (if fortified). “Milk and water are the healthiest choices, and water is the best option between meals.”
The American Heart Association (AHA) recommendations are similar.
I think there are a few things that are important to point out. First, “or it’s equivalent” means that ~600 mg plant-based calcium would fulfill these same recommendations. Second, AAP is sponsored by Milk Life. America’s Milk Companies have much to gain by perpetuating the myth that drinking a lot of milk is healthy.
There are some problems with milk.
Many people do not tolerate dairy. Milk is among only 8 foods that account for 90% of food allergies in the U.S. Dairy allergy or sensitivity may be due to milk proteins (casein or whey) or milk sugar (lactose), and depends on several factors including:
Some people who do not tolerate cow’s milk do fine with sheep or goat’s milk because the casein components are different.
Cow’s milk has been associated with:
Raw vs Pasteurized?
For those who do tolerate milk and dairy, consuming raw vs pasteurized products is a big debate.
Most mainstream organizations, including the FDA and the AAP, are strongly opposed to raw milk. This is based on a concern for foodborne illness and the premise that raw milk can have unsafe levels of bacteria like E Coli and Listeria.
Opponents also argue that raw milk is not more nutritious. However, at least two large studies demonstrate the protective effects of raw milk. The GABRIELA study demonstrates the protective effect of raw milk consumption on childhood asthma and atopy. The PASTURE study demonstrates the protective effect of raw milk from common respiratory infections.
I would argue that conventional milk has significant risks as well. Bovine growth hormone (rBGH) has long been used to increase milk production. But its use also causes mastitis and calls for increased antibiotics. Thus, both hormones and antibiotics are passed into the milk supply. This raises concern for precocious puberty and antibiotic-resistance.
There are better sources of dietary calcium.
In general, I recommend minimizing or avoiding cow’s milk, depending on your child. A better option might be organic goat or sheep’s milk products if they are well tolerated. If your child has a diverse diet, I think it is best to focus on calcium from non-dairy foods. The USDA provides a helpful database of foods and nutrients at http://ndb.nal.usda.gov/ndb/nutrients/index.
There are plenty of non-dairy sources of calcium. For comparison, 1 cup of milk has about 300 mg of calcium. Some alternative calcium sources include:
Vitamin D also plays a role in calcium absorption and bone health.
Vitamin D plays an important role in the absorption of calcium and phosphorus, and is essential for healthy bones and teeth.
The RDI of Vitamin D for children and adolescents was recently increased. AAP published the following recommendations in February 2011:
There are two sources of vitamin D. One source is sun exposure, which is negated by sunscreens and sunglasses. Another source is dietary, including:
Find a detailed list here http://pediatriceducation.org/2009/01/05/
Vitamin D intake is important to consider. Breastfed infants and most children need to supplement with Vitamin D. Adequate levels are complicated by genetic factors, as the Vitamin D Receptor (VDR) polymorphism is relatively common. While it is a simple blood test, most physicians do not routinely test for Vitamin D levels in children.
Many people think of milk as a protein, but it’s actually a carbohydrate. Did you know that 1 cup of 2% milk has 12 grams of sugar? Stay tuned next week for more about sugar intake in the United States. This one might surprise you!