Jillian Michaels

Dec 12, 2016

Superfoods: Can Too Much of a Good Thing Be Deadly?

When it comes to healthy eating, superfoods have gotten a ton of attention. And for good reason. Some foods naturally pack a heftier punch than others. For example, dark leafy greens like spinach and kale, which help keep your hormones in check, blow lesser greens out of the water. But too much of a good thing is often a bad thing. Too much vitamin C is hard on your stomach. Too much vitamin A is toxic to your liver and so on. Many superfoods, when consumed in excess, are similarly dangerous to your health. Here are three to be mindful of.

Tuna – Though a great source of heart-healthy and brain-boosting omega-3 fatty acids, tuna contains high levels of mercury. This neurotoxin is especially detrimental to pregnant women and children, resulting in developmental delays, and as such, tuna should not be consumed by expectant moms and kids more than twice a week. Note that canned tuna, generally made from smaller fish, often contains less mercury contamination than the larger tuna you might find on a sushi menu. Stick with line-caught tuna. Or opt for fishes that contain lower amounts of mercury, such as wild-caught salmon and rainbow trout.

Brazil nuts – This nut, found in the Amazon rainforests, is a great source of dietary fiber, calcium and iron. Brazil nuts are also one of the richest sources of selenium, which supports immune and thyroid function. A single ounce, about six nuts, contains 10 times the daily recommended value of selenium -- a fact that's problematic if you're eating them mindlessly. That’s because consuming too much selenium (more than 300 micrograms a day for adults) can be toxic, leading to digestive problems, memory lapses or hair loss. Another mark against Brazil nuts? They contain the highest amount of saturated fat (not the good kind) of any nut. You're better off reaching for a handful of walnuts or almonds.

Coffee – Relax, I'm not about to tell you to do away with your morning cup of coffee. After all, caffeine's been known to help fight everything from type 2 diabetes and pancreatic cancer to Alzheimer's disease. And when you drink it black and without added sugar, it's also a calorie-free way to get that extra jolt you need during the day. That said, drinking more than 400 milligrams a day (the equivalent of two strong cups) is overdoing it, and can lead to insomnia, heart palpitations, tremors, dehydration, and irritability. I must also stress the need to choose organic coffee beans. These crops are heavily sprayed with pesticides -- second only to cotton. Check out Lucky Jack Nitro Cold Brew coffees. Not only are they organic, they're also cold brewed, which removes acids and tannins, making it better overall.

Sources:

http://www.ncbi.nlm.nih.gov/pubmed/20821440

http://www.ncbi.nlm.nih.gov/pubmed/22165838

http://www.ncbi.nlm.nih.gov/pubmed/17127727

http://www.ncbi.nlm.nih.gov/pubmed/12519715

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