There’s no argument that certain foods do a body good. These so called super foods are chock-full of disease-fighting compounds and other healthy nutrients. However, as Dallas-based registered dietitian and nutritionist Jennifer Neily points out, too much of anything has a downside.
Even if it’s good for you, "the dose is the poison," she said.
Neily describes what happens when you go overboard with these five super foods.
Thanks to its high dose of antioxidants, iron and calcium, kale is the trendiest of super foods, the star ingredient in everything from salads to green smoothies. Be careful though, said Neily. As wonderful a green as kale is, overdosing on it, or any other cruciferous veggie such as broccoli or cauliflower, may interfere with the thyroid gland’s ability to uptake iodine. Theoretically, this could slow down thyroid function, leading to a condition called hypothyroidism.
Neily said you’d probably have to eat a field full of kale to get into trouble, but if you’re on thyroid medication or prone to thyroid problems, check with your doctor to make sure this super food doesn’t become a super villain in your diet.
No question that grapefruit is packed with vitamin C, fiber and potassium. But because it contains phytochemicals that block special enzymes in the intestinal wall, this citrus fruit also prevents many drugs from being properly absorbed. To date, grapefruit and grapefruit juice have been found to interact with at least 85 different medications, many of which treat high blood pressure, cholesterol or HIV.
If you’re a grapefruit lover who takes medication, check with your doctor. You may have to give up your favorite vitamin C fix to ensure your medication works the way it’s supposed to.
The goji berry, also called the wolf berry, grows on a shrub native to China. For the past few years it’s been a ubiquitous presence in every detoxifying drink and “healthy” snack you can think of. Neily praises the fruit for being loaded with an usually high amount of amino acids and protein, but says that eating too much of it can cause digestive problems.
Most people can munch on goji berries in moderation without any ill consequences, Neily said. But if you take blood thinners or medications for high blood pressure or diabetes, ask your doctor about possible drug and medication interactions. Neily also said that supplements containing goji berries are largely unregulated, so you can never be sure of dose or purity of the ingredients.
Nuts may be small packages but they deliver big health benefits. They’re high in protein, heart-healthy fats and a long list of vitamins and minerals. They’re the ultimate super food –- unless you happen to be prone to kidney stones, Neily advised.
Nuts contain high amounts of oxalates, a chemical that has been shown to increase kidney stone formation, according to the Cleveland Clinic. Other super foods that are red flags for kidney stones: beets, spinach, rhubarb, strawberries, chocolate, tea, wheat bran, and all dry beans.
Neily once went on a carrot kick, eating up to a cup a day of the crunchy veggie over a long period of time. Though it didn’t endanger her health, the palms of her hands turned bright orange, a condition known as carotenemia.
Though orange skin may clash with your clothing, it’s otherwise harmless. The beta-carotene found in carrots and tomatoes is water soluble so it isn’t toxic and won’t build up to dangerous levels in your liver. Still, the color of your skin shouldn't give away your favorite food.