Posted tagged ‘bone health’

A user’s guide to the confusing world of milk

March 25, 2013

The Pediatric Insider

© 2013 Roy Benaroch, MD

Emily Z. wrote in about a recent study linking lower-fat milk with obesity. She also wondered about omega-3 fortified milk—could it be worth the money? Emily wants to know, “How did the dairy section of the store get so complicated?”

Milk sure has gotten complicated. You’ve got, of course, milk—the white stuff that comes out of cows—in different varieties of fat content, and lactose-free versions, too. And now soy milk, and rice milk, and almond milk, and hemp milk. And organic milk. Fortified with omega-3 acids, like DHA and ARA! And don’t forget goat milk, which has natural goaty goodness. AAAAAA!! How can you decide?

First, let me suggest a definition to start with: milk is a beverage that’s high in protein, and has other nutritional stuff in there too. It’s a great food for mammal babies like our own, and for about the last 8,000 years humans have domesticated animals to continue to drink milk and eat dairy products well past infancy.

Is milk necessary at all? For babies, yes—they can’t really eat other things. Rarely does one see a one-month-old thriving on Doritos Locos Tacos. By about 9 months of age, human babies are starting to get a significant chunk of their calories from solids, and by 12-15 could probably do just fine without any milk at all. Some will just refuse it. Still, milk is an easy and tasty source of protein and calcium, so it’s traditionally a part of a child’s diet for many years.

What’s with all of the milk variants, then? Are they better than ordinary cow milk?

Ordinary, full-fat milk has about 4% milkfat in the USA. It used to be thought that infants needed that high milkfat, but a 2008 AAP statement corrected that misimpression, and their most recent statement on cardiovascular health reiterated that for families with heart health or obesity concerns (that should be all of us), low fat milk is appropriate starting at age 1. A recent study from the BMJ, reviewed here, questions that wisdom by linking lower fat milk with increased weight—but that’s probably an example of logical reverse causality. Families with high weights and weight concerns choose lower fat milk, explaining the association. In other words, it’s not the milk that causes the excess weight, but the excess weight concerns that cause the choice of lowfat milk.

There’s overwhelming evidence that too many US kids get too many calories. To me, it makes sense to choose lowfat or skim milk products as soon as babies wean from mother’s milk or formula at 12 months. We’ll have to see if better evidence appears to put that in question.

When should other kinds of milk be considered?

Rice milk – this isn’t milk. It’s high-carb, and low-protein. Drink it instead of apple juice, if you want. But it isn’t a milk substitute at all.

Soy and almond milk – good for those who want to avoid cow’s milk, or for those allergic to cow’s milk. There may be some cross reactivity with soy especially, so beware. All non-mammal milk is lactose free.

Organic milk – I don’t think it’s worth the extra cost. The main concern seems to be the use of supplemental cow growth hormone by many conventional dairies to increase milk supply. There’s zero convincing evidence that this is harmful to humans, and zero biologic plausibility that it could cause trouble for our kids. To me, my main objection is that it may be unhealthy or cruel for the cows.

Raw milk – ew. Stay away from unpasteurized things loaded with nasty microorganisms, OK?

Lactose-free milk – great for those with lactose intolerance. That means babies and young children almost never need it. Lactose intolerance is essentially non-existent in newborn humans and other mammals, because human milk is loaded with lactose. It develops later in life, typically in teens or young adults.

Hemp milk – honestly, I have no idea what this is for. Sounds groovy.

Goat milk –expensive! It’s deficient in micronutrients like folate, and has no advantage over cheap and readily available cow’s milk. Still, it’s got that goat cache.

Omega-3 fortified milk – Omega-3s are so-called essential fatty acids that are part of brain and retina tissue. Children probably need some, and we really don’t know how much is ideal or sufficient. Conditions of omega-3 deficiency are difficult to identify, and may not even exist. Still, it’s probably a good idea to eat fish once in a while, or try an omega-3 supplement of some kind. I don’t know why it ought to be added to milk in particular. I wonder if they’ll make a Nestle Quik Fish Flavor?

Confusing? You bet. I pretty much just drink conventional skim. Though sometimes, a nice Café au Lait hits the spot. Mmmmm.