Not everyone agrees that saturated fat is a problem.
We’re told that saturated fat is bad for your heart. But is saturated fat from plants different than saturated fat from meat or dairy?
Nutrition Diva is hosted by Monica Reinagel. A transcript is available at Simplecast.
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Hello! This is Monica Reinagel and you are listening to the Nutrition Diva podcast. Welcome. This week’s episode was suggested by Andrea, who wrote:
“It seems that people should moderate their intake of saturated fats. However, I’m seeing so many influencers (some who are physicians) claiming that plant-based saturated fats like coconut oil are ok. Most research seems to just focus on saturated fat in general. Does it matter if it’s plant-based or not or is all saturated fat created equal?”
Before we dig into the differences between plant- and animal-based saturated fats, it’s worth pointing out that not everyone agrees that saturated fat is a problem. Recent reviews have failed to find a strong link between saturated fat intake and disease risk (or mortality), and the medical establishment is slowly (so slowly!) starting to rethink its position on this.
The primary charge against saturated fat is that it increases your cholesterol levels, which presumably raises your heart disease risk. But a meta-analysis of 21 studies involving more than a quarter of a million people showed that the total amount of saturated fat you consume has no significant influence on your heart disease risk. What's more, three-quarters of the people who end up in the hospital due to heart attacks have normal cholesterol.
In fact, new research suggests that saturated fat may actually play a role in reducing your risk of heart disease. I talked more about that in episode #375.
For me, the frustrating thing is that researchers and policymakers insist on looking at nutrients in isolation, without enough consideration of the context in which they are eaten. After all, if I tell you to eat less of something, you're probably going to eat more of something else instead. And what you replace a food with is just as important as what you're cutting out. Is your effort to reduce saturated fat causing you to eat more sugar? I'm not sure that's a net gain.
But, to return to Andrea’s question, there are some meaningful differences between the saturated fats found in plant- and animal-based foods.
All fatty acids have a sort of spine or backbone made up of linked carbon molecules. This carbon "backbone" might have only 8 carbons or as many as 18. Lauric acid, for example, is a saturated fat with 12 carbon molecules in its backbone, while stearic acid has 18.
Chain length makes a big difference in how the various fatty acids act in the body, including how they affect cholesterol levels. Lauric acid, a saturated fat found in coconut and palm kernel oil, tends to raise both total and LDL (“bad”) cholesterol levels. Stearic acid, on the other hand, which is much more abundant in animal fat, has no effect on cholesterol levels.
I also want to point out that animal sources of saturated fat, such as meat and dairy, contain large amounts of unsaturated fat as well as saturated fat. The fats in coconut and palm kernel oil, on the other hand, are almost entirely saturated.
How does coconut oil affect cholesterol?
A 2016 review of 21 studies found that: “coconut oil generally raised total and LDL cholesterol to a greater extent than unsaturated plant oils, but to a lesser extent than butter.” And while they don’t go so far as to say that consuming coconut oil increases your heart disease risks, they conclude that “replacing coconut oil with unsaturated fats would [lead to a] reduction in risk factors for cardiovascular disease.”
My take home from that is plant-based saturated fats may be slightly less bad for cholesterol than animal-based saturated fats but, if cholesterol is your concern, unsaturated oils (such as olive oil) are the way to go!
But, of course, the heart is not our only organ. And there’s also a lot of buzz right now about coconut oil being good for your brain.
The primary argument for coconut oil as a brain-health booster is that it is rich in medium-chain triglycerides, or MCTs, which are metabolized a little differently than most types of fat. The MCTs in coconut oil break down into ketones, which can be used by brain cells for fuel. The idea is that supplying the brain with some extra fuel might make it run better.
Under normal circumstances, brain cells use glucose for energy. But because your brain is so important to your survival, there’s a back-up plan. If you run out of glucose, your body starts to convert stored fats into ketones, which are transported to the brain. It’s a little like having a back-up generator for your house. If you lose power during a storm, the back-up generator will kick in to keep the lights on.
Although it’s certainly better than being in the dark, most back-up generators are designed to be used only in emergencies until regular power is restored. Similarly, although they will gladly use ketones when no other energy source is available, healthy brain cells will preferentially burn glucose if it’s available.
So the fact that coconut oil supplies ketones doesn’t necessarily mean that the brain will use them for fuel. And perhaps that’s why I can’t find any studies showing that simply adding coconut oil to the diet leads to improvement in cognitive function in people with normal brain function.
People with Alzheimer’s disease, on the other hand, do not have normal brain function. In Alzheimer’s disease, brains cells can become resistant to the effects of insulin, meaning that they don’t take up glucose very effectively. This has led some to describe Alzheimer’s disease as “Diabetes of the Brain,” although this is a bit of an oversimplification.
PET scans of Alzheimer’s patients show that areas of the brain that are having trouble utilizing glucose will readily take up ketones. So the idea that coconut oil could help people with Alzheimer’s by providing an alternate source of fuel is completely plausible.
And we’re starting to see more clinical research on coconut oil as a therapy for Alzheimer’s disease. Investigators are trying to determine what percentage of patients see improvement in cognitive function with coconut oil (or compounds derived from coconut oil), which types of patients get the best results, how much improvement those people see, how long the improvement might last, how much you have to take to get the best response, and whether there are any side effects or risks at the effective dose.
I was particularly intrigued by a small pilot study, which found that a Mediterranean diet enriched with coconut oil (instead of olive oil) led to measurable improvements in certain cognitive scores after 7 days. Because, of course, the foods and nutrients that we consume don’t affect our bodies in a vacuum. The context of your overall diet will have a big impact on how any single food or nutrient affects us.
The Mediterranean dietary pattern is already associated with improved health and longevity, and beneficial effects on brain health and cognition. So plugging coconut oil into that context is likely to have a bigger impact than simply adding coconut oil to a less healthful dietary pattern.
So here’s my bottom line: While I think that coconut oil and other foods containing saturated fats can absolutely be included in a healthy diet, I wouldn’t recommend using coconut oil (or butter, for that matter) as your only source of fat. Monounsaturated fats (such as those found in olive oil and avocado) and polyunsaturated fats (such as those found in flax and fish) also have clear health benefits that I wouldn't want you to go without. Getting some of each is probably the best way to maximize your benefits and minimize your risks.
And, as long as we’re on the subject, just as I don’t advise going on a very low-fat diet, I also don’t recommend a diet that is extremely high in fat. At the risk of sounding like Goldilocks, my best advice (which is supported by the preponderance of evidence) is to consume a balance of high-quality carbohydrates, proteins, and fats.
Before I wrap up today, I wanted to let you know that I am going to be hosting another round of my popular 30-Day Nutrition Upgrade program. We’re going to kick it off on March 18th. If your eating habits could use a little upgrade and you’re up for a fun (and eminently doable) challenge, I hope you’ll join us. All the details are at NutritionOverEasy.com/upgrade