We’re all used to watching nutrition pendulum swing back and forth, back and forth. You know what I mean:
One nutritionist blogger made a big list of advice she’s read, which is subject to change without notice:
- Don’t eat eggs, they are too high in cholesterol.
- Really, don’t eat any fat because it is all bad for your heart.
- Don’t drink caffeine containing beverages.
- Don’t drink soda or juice, they are full of sugar.
- Don’t drink diet drinks because they will give you cancer.
- Drink only water, but be careful because the bottle is harmful and tap water is full of contaminants and the natural spring water is really bottled from the tap at the bottling company.
- Don’t use salt in cooking and avoid all foods made with salt.
- Oh yeah, you can use sea salt or Himalayan salt.
- Don’t eat butter, only eat margarine.
- Oh yeah, don’t ever eat margarine because it contains trans fat.
- Oh yeah, don’t eat any fat.
- Oh yeah, eat as much coconut fat as you want, it’s a good saturated fat.
Last month, JAMA (Journal of the American Medical Association) took on the issue of whole-fat vs. non-fat dairy consumption: which is better for us?
tl:dr version: they don’t know. But they want us to eat low-fat dairy anyway.
It’s not for lack of trying that they don’t know whether high-fat dairy or no-fat dairy promotes or detracts from health, and in what ways. They’ve tried. Oh, they’ve tried a lot. But the results are conflicting.
…some recent studies have suggested that high-fat milk, cheese, and yogurt are at least as healthful as their low-fat or nonfat counterparts, and their authors are questioning the wisdom of advising people to avoid whole milk and products made with it.
JAMA Dec 5, 2018
“I don’t think there’s enough evidence to recommend low-fat dairy,” said cardiologist Dariush Mozaffarian, MD, dean of the Friedman School of Nutrition Science and Policy at Tufts University. However, Mozaffarian added, “I don’t think there’s enough evidence to recommend whole-fat dairy, either.”
Uh, okay. But why isn’t there enough evidence to answer this question?
Part of the problem is dairy’s fault. Well, not really. But dairy products are not all created equal. Some cheeses are fermented, and some yogurts have probiotics, says Frank Hu, nutrition chair at Harvard School of Public Health.
Also, we eat dairy in different ways, Hu says:
JAMA again
For example, Hu said, while US consumers chow down on cheeseburgers and pizza, Europeans are more likely to eat cheese for cheese’s sake, not as a topping for foods that without it are already high in fat or sodium or both.
When researchers try to study the effects of dairy fat intake, they have to deal with the problems of which dairy products may be responsible for which effects, and which populations are affected by these results, as different regions eat different dairy products at differing rates.
Okay, fine. Maybe we need to throw some fancy technology at the problem– how about looking at biomarkers and seeing if there are correlations with risk for heart disease and other potentially related health problems?
They did that, too. No luck.
There are ongoing observational studies, where researchers observe and measure lots of features of participants who are consuming varying amounts of dairy fat in their diets over time. But even when they get results from these studies, they don’t tend to trust them:
[Mario Kratz, nutrition professor, University of Washington] “…people who eat the most full-fat dairy products in observational studies are usually among the ones who gain the least amount of weight.” That seems counterintuitive, but …“it’s very likely that there’s a type of compensation going on.” Low-fat or nonfat dairy isn’t as filling as whole-fat dairy, so people might end up craving unhealthy snacks if they opt for the former, he said. However, he added, “I would never recommend people consume large amounts of butter and cream.”
Still JAMA; I’ll let you know when it changes.
Hey Mario– why wouldn’t you recommend that people eat lots of butter and cream? You just said there’s not evidence that it’s bad for us.
Well, maybe Mario is just following the US Dietary Guidelines on Dairy, which say this:
- Recommendations are 2 cups (or the equivalent in yogurt or cheese) for children ages 2 to 3 years, 2½ cups for children ages 4 to 8 years, and 3 cups for teens ages 9 to 18 years and for adults.
- Fat-free and low-fat dairy are advised.
Frank Hu is of the same view. Even though there doesn’t seem to be much firm evidence that high-fat dairy is bad for us (and there’s some evidence that it’s good for us), he says he doesn’t expect nutrition recommendations to change soon. Why? Because “more research is needed to examine health effects of different types of dairy products in diverse populations.”
So, we’re back to they don’t know. But they are still recommending low or no-fat dairy consumption.
You might think: well, better safe than sorry. But the thing is, they don’t know which is safer– no-fat or high-fat dairy. And I would be very sorry to have to eat low or no-fat dairy, as it doesn’t taste like anything to me. But Frank Hu says we shouldn’t stress about it; “Overall dietary pattern is very important, and dairy is only 1 of many food items on our plate.”
Excellent. In that case, I am going to not stress and enjoy these.
What do you do when you read some new nutritional advice? Do you take it with a grain of salt (provided you don’t eat low-sodium)? Do you shift with the pendulum? Do you ignore them all? I’d love to hear from you.
New nutritional advice usually annoys me. Are eggs good or not? I am an egg fanatic. And I adore full fat milk, yogurt and cheese. At most, when I hear eggs and full fat dairy are good again I rejoice! I march off to buy delectable cheese and expensive milk produced by happy Guernsey cows. I eat eggs regularly regardless of what the food guide gods are dictating. The real issue around good nutrition and difficulties eating well, I think, has much more to do with not knowing how to cook or how to listen to what your body needs. I am extremely fortunate to be the product of foodie parents. I was never a picky eater either. Apparently, as a little girl I would amuse them with my willingness to eat anything.
Rather than being obsessed with the nutritional value of every morsel we shove in our mouths we need to develop a better relationship with food. Learning to cook is one step in the right direction. Perhaps reviving home economics classes in school. They at least used to involve cooking. Haha…my old home economics teachers would be wildly impressed at my cooking prowess even though they were pretty horrified by my hap hazard ways in the school kitchens.
Everything in moderation. Maybe that’s the real key. I groan every time I read some new nutritional advice. Go forth and enjoy full fat foods but be moderate.
Thank you for an excellent post and for putting words to my frustration as a Registered Dietitian. I lament over advice I have given in the past that was given with the best information available at the time, but has since been called into question. Same goes for trying to be a responsible Nutrition blogger, as I’m sure you know from the work that would have went into this article! Each article leads to another, and another, to check up on study design and interpretation of results etc. Science itself is as fallible as the people who conduct it, and I frequently feel my hands are tied at trying to make helpful recommendations to clients because as a regulated health professional, “there is just not enough science to responsibly recommend that at this time”.
Sometimes I feel like it makes me sound like I live in a cave, or under a rock… how could I possibly not fully endorse something that everyone is talking about? Because there are not enough randomized, controlled trials to prove and re-prove and re-re-prove it. But you know who does make confident, definitive recommendations for the specific functional foods, or supplements or diets? The non-regulated, alternative health professionals. And who would you rather take advice from? Someone who can make confident, enthusiastic recommendations or someone who is cautiously guarded against something that could be misleading or cause harm? If there is no harm, i.e: financial harm, or the risk of turning away from proven conventional treatment, such as insulin, then I often suggest a “try it and see” approach.
In the case of dairy, I think that what is confusing is that we are not comparing apples with apples. Some people are believers in how nutritious these foods SHOULD be. The studies that are NOT being done, are the ones that would compare our industrially-produced dairy and meats (i.e: grain-fed) with the old-fashioned way (grass-fed). The theory is that the flesh and by-products of grass-fed animals produce a completely different nutrient profile: omega 3 fats and other healthy fats vs some of the unhealthy fats in today’s typical grocery store options. And in those cases, the full-fat version would be even better. Unfortunately, no one is going to pay for those studies.
Thanks again for the great read!!
Thanks so much for the kind words. Yes, it’s got to be frustrating to give people information based on years of professional study and clinical experience, and then they flash an article that says “DO THIS AND YOU’LL HALT AGING!” Argh.
thanks for summarizing this field so well, Catherine. It really points to the difficulty and uncertainty in nutritional research in humans. Either the studies are epidemiological–with inherent biases and genetic and cultural factors that may influence the outcomes. Or far less common are tightly controlled studies with people eating highly controlled diets for a period of time. For example, a group of volunteers eat 6 eggs daily for a month and see how their cholesterol changes. These can demonstrate biological effects of diet in a “pure” way but obviously limited because they are so artificial and so time limited. And though their cholesterol may rise, that doesn’t even answer what we really care about–do they get heart disease earlier, or live shorter or unhealthier lives in some way?
Just to add to the dairy information–a recent article in The Lancet looked at dairy consumption in 136,000 people from 21 countries in 5 continents. A much broader sample than we usually see. The data included 9 years of follow up. The conclusion:” Dairy consumption was associated with lower risk of mortality and major cardiovascular disease events in a diverse multinational cohort.” The hazard ratio was 0.83 for total mortality and 0.78 for major cardiovascular disease. Cheese consumption had a trend to lower composite outcome, though missed statistical significance .Butter consumption was low and not associated with lower–or higher–mortality or cardiovascular outcomes. Drink your milk!
the link: https://doi.org/10.1016/S0140-6736(18)31812-9
Thanks Dan, for the very helpful additions here. Yes, not all dairy fat is created equal, but it’s looking pretty good for us. It would be interesting to get inside those big cohorts to see more information about which dairy products were consumed and in which portions. But that is where we get methodological limitations– food recall studies aren’t reliable if you’re looking too closely and with too few people. But the overall message is pretty good here. And I’m saved from feeling bad about not eating no-fat yogurt and skim milk (yuck!)