Is cow’s milk good food for people, especially people with diabetes? The American Diabetes Association (ADA) and the U.S. Department of Agriculture (USDA) say yes. Given how I feel about ADA and USDA’s record on nutrition advice, I think we should check for ourselves.
ADA recommends two to three servings of low-fat milk (or other low-fat dairy food such as cheese and yogurt) each day. “Including sources of dairy products in your diet is an easy way to get calcium and high-quality protein,” according to their nutrition page.
USDA says three cups a day for people age nine and up. But what do independent experts say? And what does the data say?
Many disagree about milk’s being healthy. Dr. Mark Hyman, author of The Blood Sugar Solution, wrote,
“I typically advise most of my patients to avoid dairy products completely… From an evolutionary point of view, milk is a strange food for humans. Until 10,000 years ago we didn’t domesticate animals and weren’t able to drink milk… The majority of humans naturally stop producing significant amounts of lactase — the enzyme needed to [deal with] lactose, the sugar in milk — sometime between the ages of two and five.”
OK. So some experts disagree with the government. But we have to start at the beginning. What is milk anyway?
What milk is made of
Milk is food produced by mammal mothers to feed their young. Mammal milks are all similar, but they have important differences in the specific proteins. It may be that cow’s milk is not a good match for most human populations.
Milk has significant amounts of fat, protein, and carbohydrate in one package. Normal cow’s milk contains 30–35 grams of protein per liter, mostly in the form of casein. It also contains dozens of other proteins in small amounts, various minerals, and vitamins A, B complex, C, D, K, and E.
What could be wrong with that? Let’s look a little more closely.
Milk protein linked to Type 1 diabetes?
There are four different types of casein proteins, called alpha-S1, alpha-S2, beta, and kappa caseins. Other milk proteins are called “whey” proteins.
A variant of beta-casein known as A1 beta-casein has been implicated in causing Type 1 diabetes. In genetically vulnerable children, A1 beta-casein may set off an immune response that later turns against the beta cells in the pancreas.
Children who drink cow milk have been found more likely to develop Type 1 later on. Other scientists say this evidence is weak and the studies were flawed. I think children should be kept off cow’s milk formulas at least until their first birthday.
The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) defines a serving of dairy as 8 ounces of nonfat or low-fat milk or yogurt.
This low-fat advice appears unsupported by science. Most of the good stuff in milk is in the fats. According to Wikipedia, “the fat-soluble vitamins A, D, E, and K along with essential fatty acids such as linoleic and linolenic acid are found within the milk fat portion of milk.”
Some evidence supports milk fat as being protective against Type 2 diabetes. A study published in the December 2010 issue of Annals of Internal Medicine followed 3,736 men for 10 years and found that those who had the highest blood levels of a type of fatty acid from whole-fat (not nonfat) dairy foods had 60% less chance of developing Type 2 diabetes than men with the lowest levels.
As one of the authors commented, “This is an extremely strong protective effect, stronger than other things we know can be beneficial against diabetes.”
Several other studies have demonstrated that dairy consumption lowers risk for insulin resistance, metabolic syndrome, or diabetes. Researchers credit a fatty acid found in dairy products, trans-palmitoleic acid, as the possible protective compound.
In various studies, higher levels of trans-palmitoleic acid were associated with numerous desirable outcomes: lower body-mass index, smaller waist circumference, lower triglyceride levels, lower levels of C-reactive protein (a marker of inflammation), lower fasting insulin levels, and less insulin resistance.
Milk sugar is called lactose. Lactose gives milk its sweet taste and contributes approximately 40% of whole cow’s milk’s calories.
Lactose can definitely raise your blood glucose. An enzyme called lactase splits it up into glucose and galactose. Because this split takes time, some nutritionists say lactose converts to blood glucose relatively slowly (that is to say, it has a low glycemic index or GI).
But others say that dairy may have a low GI but it stimulates insulin as if it had a high GI. Loren Cordain, PhD, of Colorado State Department of Health and Exercise Science, believes this may be due to the combination of lactose and some of the amino acids in whey proteins.
Cordain, author of The Paleo Answer, says the insulin response to milk is “extreme,” and advises people concerned about diabetes to avoid milk products.
It’s hard to reconcile the supposedly healthful affects of dairy fat with the supposedly harmful effects of dairy sugar. Should we drink it or not?
Different kinds of milk
There are other milks besides human and cow. Goat milk is gaining popularity. Camel milk is said by many to be extremely nutritious. It’s now for sale in the U.S. Vegan milks include soy milk, rice milk, and almond milk.
You might consider buying either free-range, grass-fed organic milk or using a vegan alternative. According to Discovery Health, milk cows are given hormones to increase their milk production and antibiotics to decrease infections. Neither of these is good to eat.
People who don’t have sufficient lactase to digest lactose will be “lactose intolerant,” and may suffer diarrhea, intestinal gas, cramps, and bloating from drinking milk.
It is estimated that 30 to 50 million Americans are lactose intolerant, including up to 75% of Native Americans and African-Americans, and 90% of Asian Americans.
Lactose-free or reduced lactose milk is available. It has been treated with lactase to break lactose down, so it doesn’t cause abdominal problems. It is sweeter than regular milk and has a higher glycemic index.
So is milk good or bad? I am confused. How has it been for you?
Want to learn more about milk? Read “Full-Fat or Low-Fat Dairy: Which Is Best?” by certified diabetes educator and registered dietitian Amy Campbell.