The other day, a news headline claiming that "low-fat dairy intake may raise Parkinson's risk" caught my attention.
The study, run out of Harvard T.H. Chan School of Public Health in Boston, analyzed data from about 129,000 participants over a 25-year study. In that time, a little more than 1,000 participants developed Parkinson's.
According to the researchers, those who consumed at least one serving of skim or low-fat milk a day had a 39% higher risk of developing Parkinson's versus those who consumed less than one serving per week.
The problem with this type of "analysis study" is that it doesn't prove anything...
The 1,000 folks who developed Parkinson's represented about 0.8% of the group. But we know in the general population, the individual lifetime risk of developing Parkinson's is about 1%. Even taking into account that the span was 25 years instead of lifetime, it still puzzles me that this amount is lower than the general population.
It turns out, Parkinson's is a complex disease with many possible factors. We know that specific genes are tied to it and that 10%-15% of cases are genetic forms of the illness. The remaining 85%-90% of cases are "idiopathic." That means we haven't figured out the root cause yet.
From my medical training, I know that pesticides get most of the blame. In 2015, a study published in Neurology found that folks with Parkinson's had higher levels of certain pesticides in their brains... These folks also drank more milk. Researchers knew from the study population that the pesticide heptachlor epoxide was prevalent in the area's milk supply. (The research is fascinating. You can read an interview with the lead author right here.)
One of the points in that study was that these pesticides are fat-soluble, meaning they get absorbed by fats. That's one of the reasons whole milk often gets a bad reputation... The more fat, the more pesticides potentially exist in the milk. It's the same reason pesticide levels are higher in fatty fish and fatty cuts of meat.
But low-fat or skim milk isn't any better for you.
You see, low-fat milk has been on my "avoid" list for a long while. Starting in the 1950s, docs started advising folks to use margarine and skim milk instead of butter and whole milk. It was the beginning of America's delusional obsession with low-fat diets.
I knew it was bunk back in medical school. Avoiding fats leads to many issues, a few of which we've covered before (here).
Milk itself has the worst reputation because of its sugar content.
One study published in the British Medical Journal actually found that milk was associated higher mortality. The mortality rates for men and women participating in the survey increased with each daily glass of milk consumed.
The researchers believed the cause for the higher mortality may be galactose, a sugar found in all types of milk that increases inflammation. As I've written before, inflammation is linked to many diseases, including heart disease, diabetes, and arthritis. These findings call into question the age-old prescription of drinking more than one glass of milk a day to prevent fractures.
So although full-fat milk likely increases your pesticide consumption, low-fat milk has all the sugar with fewer calories, meaning folks drink more of it. That's because as we replace full-fat with low-fat foods, we crave the missing calories. Our bodies then seek to replace the calories, often making us crave carbohydrates, sugars, and more. (You can read more on the low-fat diet delusion right here.)
For example, in a study last year in Circulation, those who ate full-fat dairy had lower risks of developing diabetes, whether or not they gained weight. (For comparison with Parkinson's, about 40% of Americans will develop type 2 diabetes in their lifetimes.)
Do what I do... Cut back your milk consumption. Unless it's in my coffee or in a bowl of cereal, I don't seek it out. And I always go full-fat. Organic milk also offers lower levels of pesticides. If you need extra calcium, try adding other calcium-rich foods to your diet instead, like spinach, kale, white beans, and some fish like salmon or sardines.
What We're Reading...
- The National Parkinson Foundation is a great resource on everything related to this disease.
- Cleveland Clinic breaks down some of the growing evidence against low-fat milk.
- Something different: A new find makes us ask, "When did humans first walk the Earth?"
Here's to our health, wealth, and a great retirement,
Dr. David Eifrig and the Retirement Millionaire Daily Research Team
June 13, 2017