7 Superfoods With 7 Ugly Downsides You Didn’t Know About

Some foods seem to have it all. They’re nutritious, medicinally potent and great tasting. Magazines and newspapers sing their praises and urge us to eat our fill. But no food is perfect, and even those with a host of medicinal properties can have their shortcomings. Since none of these super foods come with disclaimers, here’s the flip side of seven highly touted medicinal foods.


In addition to warding off vampires, one to three cloves of garlic daily can help lower cholesterol and protect against cancers of the stomach, prostate and colon. Garlic’s antibacterial and antifungal properties also boost the immune system. But before you start popping cloves, realize that they’ve got to be crushed to make their benefits available. The key healthful ingredient, allicin, only forms when exposed to air. Similarly, when you cook with garlic, let the crushed or chopped cloves stand for 10 minutes first. And if you’d rather take a garlic supplement, make sure it contains allicin.

Not everyone’s gonzo about garlic. Ayurveda, the traditional Indian healing system, cautions that garlic heats the body, so it could aggravate problems with digestion, hot flashes, excessive body heat or tendencies to be impatient or angry. And although garlic thins the blood, which can help lower blood pressure, it also increases the risk of bleeding if you’re having surgery or are taking blood thinners, including aspirin.

Leafy Greens

When measured on the good-for-you scale, kale, collards, mustard greens and spinach reign supreme in the vegetable world. High in calcium, antioxidants and the phytonutrient lutein, leafy greens may help prevent cancers of the breast, colon and prostate. And a recent study shows that lutein may even help reverse macular degeneration. Of the four, kale contains the most antioxidants and has high levels of easily absorbed calcium.

That’s all good, but spinach poses a potentially painful problem. Though rich in potassium, folic acid and carotenoids, its green leaves contain high levels of oxalate, which can contribute to kidney stones. If you’re prone to calcium oxalate stones (the most common), limit your spinach intake.

Also, long journeys from field to table and warm temperatures can destroy up to half of these greens’ phytonutrients. So buy local-grown greens whenever you can, and eat them soon thereafter.


The American Heart Association recommends eating two servings weekly of cold water, fatty fish such as salmon for a good reason. High in protein and omega-3 fatty acids, salmon may lower the risk of heart disease, stroke, Alzheimer’s disease and depression. However, not all salmon warrants unqualified praise. Ninety percent of the salmon eaten in the United States is farmed rather than wild, and it contains higher levels of polychlorinated biphenyls (PCBs), a probable carcinogen. Farmed salmon is also more likely to be raised in polluted water and to face diseases not typically found in wild stock. Wild salmon may contain fewer toxins than farmed fish, but mercury contamination remains a problem.

Unfortunately, the ocean populations can’t support the world’s appetite for this nutritious fish. So buy wild salmon that’s been certified by the Marine Stewardship Council as sustainably harvested. For farmed salmon, follow guidelines on safe levels for consumption (see www.oceansalive.org), and cut away the fat and skin before cooking to limit the PCBs. Even better, alternate salmon with sardines or anchovies, which have fewer contaminants and can withstand larger harvests.

Olive Oil

Popeye was right: Olive oil deserves our love. In 2004 the FDA approved the claim that two tablespoons of olive oil daily may reduce the risk of coronary heart disease. A recent study shows it may also block the action of the Her-2 breast cancer gene.

To ensure that you receive all of these benefits, buy extra virgin olive oil, rather than refined or light, both of which are treated with chemical solvents that destroy many of the oil’s nutrients. Also, choose oil in dark containers because light can damage the antioxidants.

When cooking with olive oil, avoid getting the pan so hot that the olive oil starts to smoke. Excessive heat ruins the oil’s flavor and creates harmful byproducts such as trans fats.

Lastly, since olive oil is almost 75 percent monounsaturated fat, it won’t give you all the healthy fats your body needs to stay well. Supplement your diet with the polyunsaturated omega-3 fatty acids found in flaxseed and hempseed oils. You can drizzle these temperature-sensitive oils over salads and grains.


The most nutrient dense of all the nuts, almonds pack a healing mix of vitamins, protein and healthy monounsaturated fats. Just one-quarter cup delivers 40 percent of the daily value for vitamin E, and almonds may also help lower blood pressure and cholesterol—in one study, two handfuls of almonds daily decreased LDL cholesterol by 9.4 percent. Studies suggest almonds also reduce the risk for atherosclerosis and cancers of the colon and prostate.

Exposure to air, heat and pesticides can make the healthy almond a shell of its former self. Commercial roasting, for example, deep-fries the nuts in saturated fats, negating any cholesterol lowering benefit. Buy dry-roasted almonds with no sugar, corn syrup, MSG or preservatives added. If you’re roasting them yourself, do it gently at 160 to 170 degrees to preserve the natural oils. Even with that precaution, roasting significantly decreases vitamin A, pantothenic acid and thiamin levels, though other nutrients appear unaffected.

When it comes to nuts, freshness matters a lot. Buy organic almonds in their shells and, ideally, in hermetically sealed packaging. If you prefer to buy almonds in bulk, they should smell sweet and nutty, not sharp and bitter.
While whole nuts provide the most nutrition, shelled almonds are still quite nutritious, although they may become rancid sooner, especially if sliced. Keep them stored in a sealed container in a cool, dry, shady place or in the refrigerator or freezer.

Of course, anyone with nut allergies should shy away.


Nowadays no one talks about tomatoes without mentioning lycopene. And with good reason: This potent antioxidant may help prevent atherosclerosis and cancers of the prostate, breast and lungs.

In a testament to nature’s mysterious ways, lycopene works best in concert with the tomato’s other important phytonutrients rather than in isolation. In fact, in one study, lycopene alone didn’t inhibit prostate cancer cells, while the whole tomato did. Lycopene is more concentrated in tomato pastes and sauces and is better absorbed when the tomato’s been cooked or has a touch of oil. No one has tested the role of basil.

When buying tomatoes, choose the reddest you can find; yellow and orange varieties lack lycopene. Lastly, as a member of the nightshade family, which includes eggplant, potatoes and peppers, tomatoes may aggravate arthritis pain, though few existing scientific studies establish a link. If you suffer from arthritis, you may want to try eliminating tomatoes (and the other nightshades) from your diet to see if your pain improves.


In 1999 the FDA approved the claim that eating 25 grams of soy protein daily decreases the risk of heart disease. Eating soy may also protect against cancers of the uterus, colon, prostate and breast. While some studies say soy alleviates menopausal symptoms and protects against osteoporosis, the evidence is inconclusive. Controversy also exists about whether soy isoflavones, a group of phyto-estrogens that stimulate breast cell growth, may increase breast cancer risk in those prone to it. Several studies show no link, but people with breast cancer or those predisposed to it should eschew soy isoflavones supplements for soy protein itself. You’re less likely to overdose on isoflavones with soy protein, and it carries more health benefits as well.

Soy can trigger allergic reactions such as nasal congestion, asthma, fatigue and itching. Kids aged three months to two years may be particularly sensitive, though they usually outgrow it. If you suspect you’re allergic, avoid eating soy for three weeks and then reintroduce it and watch for symptoms.

Many people worry that genetically modified soy can cause organ damage and allergic reactions. Choose organic soy to avoid the otherwise ubiquitous GMO varieties.

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