The Fatal Flaw of the Vegan Diet

Fats, fats, fats.

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Dec 5 2016, 5:00pm

The first problem with vegan diets is that they're simply free from animal products. 

That's not necessarily a bad thing, but that's all the term means. By definition, vegans don't eat more vegetables, have more or less body fat, or have longer or shorter lives. A vegan diet of Skittles and bread will cause malnutrition just as easily as a diet of pepperoni and cheese.

There's a difference between vegans who know their shit and vegans who don't, in other words. Vegans who know their shit are aware that there are certain important nutrients, like vitamin B12 and creatine, that are either impossible or extremely inconvenient to consume without using supplements. (Contrary to popular belief, protein is seldom one of them—the FDA only recommends 50 grams per day to avoid a deficiency, and you can easily get that much from nuts and legumes.)

But even vegans who know their shit can get tripped up by omega-3 fatty acids. Crunchy, misleading websites abound, promising that even though omega-3s are usually sourced from fish, vegans can meet their requirements through seeds and nuts like flax, chia, walnuts, and hemp seeds. (The FDA doesn't currently have a recommended daily intake of omega-3s, but the American Heart Association recommends one gram per day.)

Here's the truth: if you get your daily gram of omega-3 fatty acids through seeds and nuts, you're not meeting your intake. You're not even close. 

What's the big deal? 

Omega-3 fatty acids are a big, big deal. 

"There are tons of reasons why they're important," says Leyla Shamayeva, a New York-based dietitian. "There are a lot of links with mental health, like improving mood and memory and lowering the risks of depression and dementia. But their main link with disease prevention is that they're anti-inflammatory, and chronic inflammation is linked to medical conditions like arthritis, heart disease and cancer." A healthy intake of omega-3s has also been linked to lower cholesterol, stronger bones, and possibly even a slimmer waistline. 

This kind of good publicity is why sales for fish oil supplements have increased by a whopping nine times since 2002, with Americans now spending $1.2 billion every year on the stuff. 

But when it comes to omega-3s, more isn't better. "There was a craze about fifteen years ago when people would load up on more and more fish oil to decrease inflammation, which was kind of misguided," says Kamal Patel, director of the independent nutrition research organization Examine.com. "In the typical American diet it's not the omega-3s that are the issue, it's the excess omega-6." You don't want to consume as much omega-3 as possible; you just want to keep your omega-3s relatively high in relation to your omega-6, because they compete for the same enzyme that processes them. Too much omega-6 means your omega-3 won't absorb well, and you'll wind up spinning your wheels.

Thing is, the Standard American Diet is positively lousy with omega-6 fats. It's in everything from nuts and chicken to seeds and processed oils, like the ones used to fry practically everything we eat. Our consumption of soybean oil alone has increased by over five hundred percent since the 1960s. A healthy ratio of omega-3 to omega-6 is about 1:2, but these days, the average person eats closer to 1:20.

Exactly what happens when we eat too much omega-6 is hard to know. (We actually stopped testing high doses of omega-6 on humans after a 1965 experiment resulted in a significant number of heart attacks.) But rodent studies and observational human trials have shown significant correlations between omega-6 intake and inflammation, heart disease, obesity, depression, and cancer

Ok, so anyway, what's so wrong with nuts and seeds?

There are three main kinds of omega-3s: eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and the plant-based alpha-linolenic acid (ALA). EPA has a stronger link with inflammation, DHA has a closer tie to mental health.

The problem for vegans is that seeds and nuts only contain ALA, while the health benefits of omega-3 fatty acids have been almost entirely linked to EPA and DHA. After chugging flaxseed oil or supping a chia pudding, the body needs to go to work converting ALA into EPA and DHA. 

And frankly, we suck at it: It's commonly estimated that just five to ten percent of ALA is converted to EPA and two to five percent makes it to DHA. To simplify matters, that means 90 percent of your typical plant-based EPA and DHA is being lost in digestion. 

To make things worse, a high omega-6 intake, which the average American has, appears to make it even harder to convert ALA to EPA and DHA, reducing that already low conversion rate by an additional fifty percent.

If that sounds like vegans will be fine if they just consume a whole lot more ALA, it's worth noting that while ALA itself has been linked to lower rates of heart disease and diabetes, high intakes of the stuff have been associated with an increased risk of prostate cancer, so doubling down on ALA may not be the best way to accrue the benefits of EPA and DHA. 

Point being, vegans need algae in their lives

Getting the benefits of EPA and DHA from nuts and seeds is very inefficient, to say the least. (It's important to note that doesn't mean you should stop consuming nuts and seeds, though—they're great sources of protein and fiber, and they contain a ton of vitamins and minerals. A daily handful nuts in particular has been linked to a longer, healthier life. But if they're your go-to source of omega-3s, you need to rethink.)

The solution: "Most plant-based omega 3s provide ALA, but the big exception is microalgae," Shamayeva says. "It's this same seaweed that fish consume that makes them so rich in EPA and DHA. The best vegan omega-3 supplements are algae-based."

Microalgae only really contains DHA, but studies have found that when vegans take it as a supplement, their EPA levels also increase substantially. Now, a gram of vegan DHA does tend to be a lot pricier than a gram of fish oil. But the good news is that you probably need less than you think—like we said, whether you're a vegan or not you don't necessarily need to load up on omega-3, you probably just need to reduce your omega-6.  

"Omega-6 could be reduced by eating less processed food," says David Katz, director of the Prevention Research Center at Yale, pointing out that limiting commercial vegetable and seed oils is a great way to do so. If you eat natural foods and avoid processed oils and fried junk, you probably don't need to stress too much.

"It's really only the vegans who eat the old bread, pasta, hummus diet, where half their diet is processed food, who need to worry about omega-6," Patel agrees. "You can even eat plenty of nuts and avocados, which contain it in relatively high amounts, without causing problems. It's once you start getting a purified source of them through cheap oils that your ratio can become too skewed."

So instead of only adding extra omega-3s to your diet, it's best to reduce omega-6 at the same time. That way, you won't add a ton of unnecessary calories and potentiate weight gain while you're trying to be healthy.  

TL; DR

Popping a microalgae supplement and cooking with oil that's relatively low in omega-6, like olive oil, avocado oil, or even a saturated fat like coconut oil, can go a long way toward improving your mental health and lowering your risk of disease.