Crying Over Spilled Milk
We are not one of those families that regularly drink a glass of milk with dinner. To be honest, I’ve always been a bit ambivalent about dairy. But I’ve discovered that my family isn’t alone in their blasé attitude about milk. Things are shifting in both the U.S. and Canada around the popularity and prevalence of milk in many people’s daily menus. New research is casting doubt on the idea that milk is an essential part of a healthy diet and that low-fat milk is the healthiest option.
Not Highly Recommended
Many nutritionists and scientists are suggesting that, in fact, humans have no inherent nutritional need for milk, other than babies for breast milk. Walter Willett, MD, DrPH, a professor of nutrition and epidemiology at the Harvard T.H.Chan School of Public Health, and his co-author, David Ludwig, MD, PhD, a professor of pediatrics and nutrition at Harvard, published a review article called “Milk and Health” for The New England Journal of Medicine which states, “…the health benefit of a high intake of milk products has not been established.” And while they found no evidence to link milk consumption with overall weight gain, diabetes, or cardiovascular disease, they did find that “In international comparisons, consumption of dairy products is strongly correlated with rates of breast cancer, prostate cancer, and other cancers.”
This shift in the way milk is viewed is significant. And more so for many Canadians who were surprised, to say the least, when in 2019, the Canadian government released new dietary guidelines that dropped specific dairy recommendations from the purview. It is now recommended that Canadians think of their daily diet as a meal plate in which half is filled with vegetables and fruits, a quarter with grains or starches, and a quarter with protein. Dairy can be part of the protein component of a meal, but no longer has its own food grouping with recommended daily intake amounts. While the U.S. has also swapped out the old food pyramid to a “my plate” style dietary guideline, getting closer in line with Canada’s approach, they haven’t ditched the dairy and continue to recommend between two and three servings a day of low-fat or fat-free dairy products for adults and children older than two and whole milk for younger kids.
Better Bone Boosters
Dr. Willett also says that evidence suggests that milk isn’t as good for bones as we once believed, pointing to large population-based studies correlating diet and health. Ironically, these kinds of studies consistently show an increase in hip bone fractures in countries where people eat the most dairy. Willett says that is consistent with the idea that a body can change how much calcium it absorbs from food, and research supports this with evidence that a person’s ability to absorb calcium is higher in countries where diets typically aren’t as rich in calcium and dairy products. As for where to get those bone-building vitamins and minerals? Turns out there may be better, cheaper, and healthier options. According to Willett, “For calcium, alternative dietary sources include kale, broccoli, tofu, nuts, beans, and fortified orange juice; for vitamin D, supplements can provide adequate intake at far lower cost than fortified milk.”
Low-Fat? No Thanks!
For years now, low-fat and fat-free milk and milk products have been widely recommended as the dairy of choice for those seeking good health. But according to the research studied by Willett and Ludwig, the truth may be the opposite. “Contrary to U.S. Department of Agriculture’s (USDA) advice to choose reduced-fat dairy, low-fat milk does not appear to have advantages over whole milk for weight control—and in children, available evidence suggests greater long-term weight gain with reduced-fat milk than with full-fat milk.” They go on to encourage the U.S. dietary standards be changed to “…deemphasize reduced-fat milk as preferable to whole milk.” There are studies now linking weight gain with consumption of low-fat milk in both children and adults.1,2
Besides the potential for weight gain, low-fat dairy products may have additional problems all their own. Studies have linked low-fat dairy to infertility in both men and women. One such study found that men who ate more conventional dairy were more likely to have poorer semen samples. It is assumed that this is because of the high concentration of xenoestrogens (chemicals that behave like estrogen which may have feminizing effects on the body) in conventional meat and dairy. Skim milk was found to have even higher concentrations of xenoestrogens than whole milk. And in the Harvard Nurses’ Health Study, the largest study of risk factors for chronic diseases in women to date, the findings showed a direct correlation between the consumption of low-fat dairy products and infertility. This study also found that a change in dietary habits, including the adoption of whole-fat dairy, helped women with infertility caused by irregular or absent ovulations reduce their risk of infertility by 80 percent.
It’s not entirely clear why any of these things are true. Perhaps the chemicals or the process used in de-fatting milk are to blame, or the absence of the necessary fat itself is the problem. Yet another theory points towards hormone imbalance in skim milk that might in turn somehow affect the hormones responsible for fertility in humans. Adding to the plausibility of this is a study correlating (often hormone-related) teenage acne with the consumption of skim milk.3
The ability to digest lactose into adulthood is the result of a genetic mutation, writes Sophie Medlin, lecturer in Nutrition and Dietetics at King’s College, London, in an article looking at the current science of milk. Milk contains a sugar called lactose which requires an enzyme called lactase to allow it to pass across the walls of the gut and into the bloodstream. It is lactase that allows a baby to absorb breast milk and it is incredibly rare for a baby to not have sufficient lactase to achieve this process. Interestingly, in certain countries and cultures where milk consumption is significantly lower, such as Japan and China, most children will stop producing lactase soon after weaning, leading to a higher prevalence of those who are lactose intolerant. Indications a person is lactose intolerant include bloating, gas, and diarrhea after consuming milk, ice-cream, or some cheeses.
In comparison, those countries that consume milk regularly, such as in Europe, lactose intolerance is less common, as most adults maintain the ability to produce lactase and are therefore able to digest milk without ill effect. In these populations only around five percent of people are lactose intolerant, writes Medlin. And for those who do have lactose intolerance, fermentation of dairy—such as with kefir or yogurt—can reduce the levels of lactose enough for even the sensitive to enjoy. Dairy fermentation developed with the consumption of dairy in some populations over the last 8,000 years, writes Medlin, and is one way that some cultures were able to enjoy milk before they developed the genetic mutation to make it easier.
Say it Ain’t Soy!
Many people may opt for soy in place of dairy. Unfortunately, there may be a correlation between dairy sensitivity and soy sensitivity according to nutritionist Kelly Dorfman, author of Cure Your Child with Food. Indeed, the research on soy milks and formulas for children suggests all children and most adults may want to take a pass. Soy—especially soy milks and tofu—are full of phytoestrogens that are best avoided by children and by adults trying to conceive as they have been shown to negatively affect reproduction and endocrine function and can contribute to thyroid problems, which are linked to infertility and miscarriage. Soy can also reduce the assimilation of minerals such as calcium, magnesium, copper, and iron, and interfere with the body’s absorption of Vitamin B12, D, and protein. As well, it contains high levels of aluminum, a known neurotoxin. Men who ate or drank soy were more likely to have lower sperm counts, as the equivalent of one cup of soy milk per day was associated with a 50 percent lower sperm count than that of men who didn’t eat soy, according to a 2008 study at the Harvard School of Public Health. Another study linked a pregnant woman’s consumption of soy to increased chances of the child in utero developing leukemia, while yet another linked soy to increased risk of infant boys being born with the male genital disorder hypospadias (when the urethral opening is on the underside of the penis, rather than at the tip), although it’s important to note that both results may be attributed more to the pesticides used in growing soy, than directly to soy itself. The issues of soy in developing organ systems are so well documented now that a number of countries discourage soy formula for infants.
On a positive note, for young children and babies, the downsides of milk are less of an issue. “If mother’s milk is not available, cow’s milk may provide a valuable substitute in early childhood,” according to the research of Willett and Ludwig.
The Cream of the Crop
I love milk in my tea in the morning, my kids occasionally enjoy a bowl of cereal, and we all love cheese and yogurt. Does the science mean we have to say goodbye to dairy forever? The important takeaway from all the research is this: Making dairy a small part of your diet, if your family tolerates it well, is fine, but quality is especially important. When I shop for dairy, especially milk, organic is the minimum standard I search for. Ideally, I’m looking for non-homogenized (when the fat globules of the cream are not broken up), grass-fed, and organic. If I can find it, I also try to get unpasteurized milk from a farmer I know. Most people don’t have that luxury, but organic milk is a standard that is now widely available in Canada and the U.S. North America is home to one of the largest organic dairy markets, worth 19.4 billion U.S. and is estimated to grow by 14.3 percent between 2016 and 2022.4
So why organic? Studies, such as one published in 2019 in the journal Public Health Nutrition where milk samples from across the U.S. were analyzed, have indicated the presence of pesticides, growth hormones, and antibiotic residue routinely found in conventional milk, often at levels that exceed federal limits. Cows that are not raised to meet stringent organic standards are fed a diet heavy in pesticide-contaminated grains. They are also routinely given antibiotics, both to keep them from getting sick from the unnatural diet, and sometimes to encourage their weight gain. In the U.S., cows can also be fed artificial growth hormones, such as recombinant bovine somatotropin (rbST) used to increase milk production. Artificial growth hormones have come under recent scrutiny from consumers despite both Canada and the U.S. asserting that there’s no evidence they can cause harm to humans. There is evidence, however, that they can harm cows: Health Canada commissioned a report in 1999 that found there was an increased risk of mastitis, infertility, and of lameness in cows treated with the drug.
Further, public advocacy groups have also weighed in, with Consumer Reports commissioning a report that asks, “…to what extent does rbST use increase the level of the hormone Insulin-like Growth Factor 1 (IGF-1) in milk, and what possible risks to public health might be associated with consuming milk with increased IGF-1 levels?” The result of this was credible evidence suggesting that IGF-1 levels are increased in milk from rbST-treated cows and that the hormone not only survives digestion, it also passes into the intestinal tract at levels that may be linked to higher rates of colon cancer. Other studies suggest it may also be linked to an increased risk of breast cancer in premenopausal women. They also found that more mastitis in cows meant more antibiotic use which could potentially contribute to antibiotic resistance in humans.
Milked in the U.S., but “Made in Canada”?
Dairy products made with U.S. milk ingredients are routinely sold in Canada and don’t have to be labelled as such. In his paper, “The Regulation of rbST in Canada,” written for the Parliamentary Research Branch, Frédéric Forge states, “It is very likely that products such as cheese and yogurt made from milk produced by rbST-treated cows have been imported into Canada.” Indeed, products for which milk is only one ingredient among many, such as ice-cream, are classified as Canadian if they are manufactured in Canada, no matter where the raw ingredients originated. So, although a Canadian farmer is legally prohibited from importing artificial growth hormones to feed to its milk cow, Canadian manufacturers are able to purchase hormone-tainted milk to use in the making of products sold within Canada. There is no guarantee your dairy products are artificial-growth-hormone-free in Canada unless you either know your farmer or the product is certified organic.
If there is no health imperative to feed our family members two to three servings of dairy daily, then we can justify the expense of treating ourselves to milk, cream, and cheese that come from the highest quality sources. Even better, there are a number of healthy alternatives for supporting bone health that can fit just as easily into your family’s diet while also providing a greater variety of nutrients.
For references visit ecoparent.ca/extras/WIN20