There are lots of things we want to do in life. Climb a mountain, write a song, watch our grandchildren grow up. But guess what? We can’t do any of those things if we don’t have our health.
Welcome to the Nutrition Facts Podcast. I’m your host Dr. Michael Greger. And I’m here to bring you evidence-based research that takes the mystery out of the best way to live a healthier, longer life.
On the show today, you’ve heard about it, you’ve read about it. It’s time for our very first non-dairy milk extravaganza! There are so many milks that aren’t from cows, it can make your head spin. Today, we count the ways.
In our first story, I recommend people switch away from using rice milk.
For kids and teens, the amount of arsenic flowing through their bodies was found to be about 15% higher for each quarter-cup of daily rice consumption. A similar link was found in adults. A study of pregnant women found that about a half a cup a day of cooked rice could raise urine arsenic levels as much as drinking a liter of arsenic-contaminated water at the current upper federal safety limit. So, that suggests that many Americans “may be exposed to potentially harmful levels of arsenic through rice consumption.”
But, you know where Americans get most of their rice arsenic from? Rice Krispies, though brown Rice Krispies may have twice as much.
“Organic brown rice syrup is used as a sweetener in organic food products as an alternative to high-fructose corn syrup.” Big mistake, as organic brown rice syrup products may introduce significant concentrations of toxic arsenic into peoples’ diets.
“Toddler formulas with added organic brown rice syrup have 20 times higher levels of toxic arsenic.” And, ‘in older children,” thanks to brown rice syrup, a few cereal “bars a day could pose a quote-unquote very high cancer risk.”
What about rice milk? A consensus statement of both the “European and North American Societies for Pediatric Nutrition recommend the avoidance of rice milk for infants and young children.” And, generally, toxic arsenic intake in infancy and childhood should be as low as possible.
To this end, “the UK has banned the consumption of rice milk for young children,” a notion to which Consumer Reports concurred, recommending no servings a week of rice milk for children, and no more than half a cup a day for adults.
The arsenic in various brands of rice milk ranges all over the place, a 15-fold difference between the highest and lowest contamination, suggesting manufacturers could make low arsenic rice milk if they wanted. Consumer Reports found Pacific brand and Rice Dream were right about average, though perhaps for Rice Dream, it appears the vanilla or chocolate flavors may be lower. Rice vinegar doesn’t seem to be anything to worry about, but rice pasta and rice cakes end up similar to pure rice which makes sense, because that’s what they pretty much are, though pasta is boiled. So, we’d expect the levels to be cut 40 to 60%, like when you boil and drain rice.
If for some reason, you just couldn’t live without rice milk, you could make your own, using lower-arsenic rice, like brown basmati from India, Pakistan, or California, but then it may have even less nutrition, as at least most of the commercial brands are fortified. Better options might be soy, oat, hemp, or almond milk, though you don’t want kids to be drinking too much almond milk. There have been a few case reports of little kids drinking like four cups a day, running into kidney stone problems, due to the relatively high oxalate content, averaging about five times more than soy milk.
Some of the latest science on soy milk includes an association with better knee x-rays, suggesting protection from osteoarthritis, and an interventional study suggesting improved gut health by boosting the growth of good bacteria, Though drinking three quarts a day, 10 to 12 cups a day for a year, may inflame your liver. Two cups a day, though, can have an extraordinary effect on your cholesterol, a whopping 25% drop in bad cholesterol after just 21 days.
An ounce-and-a-half of almonds every day, like a handful a day, can drop LDL 13% in six weeks, and reduce abdominal fat, though a cup of almond milk only contains about 10 almonds, less than a third of what was used in the study. So, it’s not clear if almond milk helps much, but there was a study on oat milk compared to rice milk. Five weeks of oat milk lowered bad cholesterol, whereas rice milk didn’t, and even increased triglycerides, and may even bump blood pressure a little bit. But, the oat milk only dropped LDL about 5%, and that was with three cups a day; so, as plant-based alternatives go, it appears soy milk wins the day.
So, why drink rice milk at all when there are such better options? There’s really not much nutrition in rice milk. In fact, there are case reports of “severe malnutrition” in toddlers who centered their diets around rice milk due to multiple food allergies. Infants and toddlers have increased protein requirements compared to adults; and so, if the bulk of some poor kid’s diet is rice milk, coconut milk, potato milk, or almond milk, they may not get enough.
Oh, yeah? Show me one case of kwashiorkor (that bloated belly protein/calorie deficiency) due to rice milk. Here you go, “severe kwashiorkor,” not in Ethiopia, but in Atlanta, Georgia because literally 99% of some kid’s diet was rice milk. So, these malnutrition cases were not because they drank rice milk, but rather because they drank rice milk nearly exclusively. But, I just use these to illustrate the relative lack of nutrition in rice milk. So, if you’re going to choose a milk, might as well go for one that has less arsenic and, more nutrition.
In our next story we look at hormonal stimulation of human prostate cancer cells by cow milk in a petri dish and ask does this translate out clinically in studies of human populations?
“Concern has been expressed about the fact that cows’ milk contains estrogens and could stimulate the growth of hormone-sensitive tumors” concern that the “consumption of dairy products could both promote the conversion of precancerous lesions or mutated cells to invasive cancer and enhance the progression of hormone-dependent tumors.”
This was initially postulated based on suggestive population-scale data like this: 25-fold increase in prostate cancer in Japan since the war. What was happening to their diets during that period? A 5-, 10-, 20-fold increase in eggs, meat, and dairy consumption, whereas the rest of their diet remained pretty stable.
But, diet wasn’t the only major change in Japanese lifestyles over the latter half century. Similarly, even though countries with higher milk consumption tend to have more prostate cancer deaths, and countries with lower milk consumption fewer deaths, there could be hundreds of confounding variables. But, it certainly does spur interest in studying the possibility.
This recent study represents the other extreme, controlling for as many factors as possible by just isolating prostate cancer cells out of the body in a petri dish, and dripping cow milk on them directly. They chose organic cows’ milk because they wanted to exclude the effect of added hormones, and just test the effect of all the growth and sex hormones found naturally in all milk.
They found that “cows’ milk stimulated the growth of human prostate cancer cells in each of 14 separate experiments, producing an average increase in cancer growth rate of over 30%. In contrast, almond milk suppressed the growth of these cancer cells by over 30%.”
But, just because something happens in a petri dish, or a test tube, doesn’t mean the same thing happens in a person. It’s just suggestive evidence that can be used in a grant application or something to get money to study actual people. There’s kind of two main ways that’s done: retrospective studies looking back, where you take prostate cancer patients, and figure out what they ate in the past, and prospective studies looking forward, where you look at people’s diets first, and then follow them for a few years, and see who gets cancer. The looking-back kind are called case-control studies, where they look at cases of cancer, and compare their diets to controls. And the forward-looking kind are called cohort studies, because you’re following a cohort of people forward. Then, if you want to get fancy, you can do a so-called meta-analysis, where you combine all the best studies done to date into one, and see what the balance of available evidence shows. Okay, so, here we go:
The latest meta-analysis of all the best case control studies ever done on the matter concludes that milk consumption is a risk factor for prostate cancer. And the latest meta-analysis of all the best cohort studies ever done also concludes that milk consumption is a risk factor for prostate cancer. An even newer study suggests that milk intake during adolescence may be particularly risky in terms of potentially setting one up for cancer later in life.
Despite hormone-related cancers being among our top killers, as pointed out in the Journal of the National Cancer Institute, “We simply do not know which hormones, and how much, are in the food we ingest. More effort has been directed at the investigation of illicit use of designer steroids by Olympians and ballplayers than to the investigation of the effect of dietary hormones on cancer, and other diseases that affect millions.” A proposal is therefore made “to monitor levels of steroid and other hormones and growth factors in all dairy and meat-containing foods”; though, to date, this has not been done.
Finally, we look at the impact of coconut milk and flaked coconut on cardiovascular disease risk. What about coconut milk which is rich in MCFA’s Harmful anyway? Harmless or helpful?
Some may remember those studies from 2007 that showed that an Egg McMuffin was McDeath on our arteries, olive oil didn’t do anything, and walnuts showed an immediate benefit. Well, that experiment was repeated, but this time with coconut milk. And the arterial reaction to coconut milk was as bad as the McDonald’s.
What about the whole food, though? Flaked coconut, which is just whole dried coconut. Research on defatted coconut flakes shows a cholesterol-lowering effect. That’s no surprise; all whole plant foods have fiber, and fiber lowers our cholesterol.
But this was for coconut flakes with the fat taken out, which isn’t available commercially. What about just regular flaked coconut that you’d buy in a store?
The fat part, the coconut oil is bad, but the nonfat part of coconuts is good. Put them both together, and does the fat win out, making it harmful? Do they cancel each other out? Or does the fiber win out, making both flaked and whole coconuts helpful?
And the answer is: just harmless, based on studies of coconut-eating Malaysians.
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Thanks for listening to Nutrition Facts. I’m your host, Dr. Michael Greger.