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8 Food Myths and Facts

Here's straightforward advice on eight "iffy" foods and ingredients.

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No matter how healthy your diet, there are always those few foods-your morning latté, a piece of sourdough bread at dinner-that leave you wondering: Should I really be eating that? 

Is it okay to eat canned tuna or drink coffee? Should everyone run screaming from gluten? There’s lots of confusion in the food world these days-and lots of conflicting answers and opinions. If your food choices have you in a pickle, you need straightforward facts and advice. Here, we examine the eight most confusing foods, and the bottom line on each.

8 Food Myths and Facts

1. Gluten. 

Ever since books such as Wheat Belly and South Beach Diet Gluten Solution hit the market, gluten has become the hapless scapegoat of the food world. For people who have problems with gluten, it’s with good reason: a sensitivity to gluten from wheat, rye, and barley can cause everything from headaches to dramatic digestive issues. But what about those who tolerate gluten just fine? Should they still be cautious, even in the absence of symptoms?

The bottom line: If you suffer from gluten sensitivity, you should avoid it in all forms. If you tolerate gluten, it’s still wise to proceed with caution. Modern wheat and other forms of gluten are different from what our ancestors ate, and the advent of packaged and processed foods means gluten is more prevalent than ever in our food supply. To avoid developing gluten sensitivity in the future, vary your grain sources; give gluten-free grains such as brown rice or quinoa a try; and minimize your intake of processed foods.

2. Coffee. 

Our favorite hot beverage has been blamed for everything from heartburn and headaches to adrenal burnout. Caffeinated coffee is a powerful central nervous system stimulant that can disrupt sleep, increase stress, and upset cortisol balance. Even decaf coffee is highly acidic and can cause gastric distress and acid/alkaline imbalances in the body. At the same time, coffee contains many antioxidants, and studies show that it actually protects the liver. Drinking coffee also protects against Parkinson’s disease and Alzheimer’s, and both caffeinated and decaffeinated coffee reduce the risk of diabetes and increase lifespan.

A recent Harvard University report noted these coffee benefits: lower blood pressure, a slower rate of weight gain with age, and reduced risks for type 2 diabetes and heart disease.

The bottom line: If caffeinated coffee doesn’t disrupt your sleep or upset your stomach, there’s no reason to avoid it. But because caffeine is highly addictive, most people increase their consumption over time-so monitor your intake and try to keep it under 200 mg per day, about the amount found in a large, strong-brewed cup of coffee. If you’re just fine with caffeine but have a sensitive stomach, try switching to black tea. It’s even higher in antioxidants than coffee, and creates a less acidic environment in the body.

3. Seafood. 

It’s high in protein, low in fat, and rich in omega-3 fatty acids, and studies link seafood consumption to decreased risk of heart disease and prostate cancer. But seafood also has its share of problems. If it came from the ocean, it’s probably contaminated with mercury. If it came from a farm, it’s likely laced with pesticides and polychlorinated biphenyls (PCBs)-man-made chemicals that are linked with behavioral problems, neurotoxicity, and possibly cancer. Canned tuna, salmon, and other fish may also contain bisphenol -A (BPA), a dangerous endocrine-disrupting chemical, from the can’s lining.

While many studies suggest that the benefits of eating seafood outweigh the risk of exposure to mercury and other toxins, there’s also the environmental problem of overfishing and pollution. Some estimates say that if current trends continue, we’ll run out of wild caught fish in less than 35 years.

The bottom line: Eating fish once a week is probably reasonable, with these caveats: Avoid large, predator fish, such as tuna and swordfish, to minimize mercury exposure. And skip the skin-it’s a main storage area for toxins. In terms of environmental impact, farmed fish reduce the risk of depleting wild populations, but carry serious environmental concerns of their own. Before you buy, visit the Environmental Defense Fund’s Seafood Selector page ( for safe seafood updates.

4. Agave. 

Once the golden child of the alternative sweetener world, agave’s reputation has been tarnished of late. It’s low on the glycemic index but high in fructose, which has been associated with weight gain, insulin resistance, and diabetes. Additionally, excess fructose consumption has been linked with an increased risk of fatty liver disease. Because agave is converted into triglycerides, it can increase the risk of heart disease.

The bottom line: Agave’s not the worst thing you can eat, but it’s not a health food. If you eat processed foods, check labels; many “natural” snacks and raw packaged foods are heavily sweetened with agave. And while an occasional squirt in your tea won’t hurt you, less-processed sweeteners (such as honey), or lower-glycemic ones (such as coconut sugar), are better alternatives. Or consider stevia. It’s backed by dozens of studies and thousands of years of historic use, doesn’t upset blood sugar, and may even balance glucose levels.

5. Soy. 

So many aspersions have been cast on this once-healthy food that it’s hard to tell what to believe. On one hand, soy is high in protein and fiber, low in fat, and contains phytoestrogens that, according to some studies, can reduce the risk of osteoporosis, heart disease, and cancer. On the other hand, most soy grown in the United States is contaminated with genetically modified organisms (GMOs). And the phytoestrogens in soy can also stimulate the growth of certain kinds of cancer. Soy is also difficult to digest, and many people are either sensitive or downright allergic to it.

The bottom line: A little organic soy won’t hurt you, unless you’re allergic or sensitive. But it’s best eaten in fermented forms (tempeh, miso, tamari) or whole (edamame). Limit your intake of highly processed soy foods–such as soy milk, soy cheese, and isolated soy protein (found in many drinks and bars)–to 1-2 servings per day.

6. Meat. 

Unless you’re vegan, you’ve probably struggled with the question of how much meat to eat. Lean meat is high in protein, essential nutrients, and conjugated linoleic acid (CLA), which protects against caner and obesity. Popular Paleo diets say that meat is essential to athletic performance and longevity and promote heavy consumption-as much as 1-2 pounds per day. But years of studies consistently show that the longest-living populations eat less meat, not more, and we know the risks of saturated fat, as well as the added hormones and antibiotics found in conventional meat. From an environmental standpoint, a diet high in meat just isn’t sustainable.

Carnitine can help put the pep back in your step, but that’s just the tip of the iceberg for this versatile nutrient.

The bottom line: If you do eat meat, choose organic, grass-fed, pastured varieties. They’re free of antibiotics, added hormones, nitrates, and other additives. Grass-fed meat is lower in saturated fat and calories than grain-fed varieties, and has higher levels of CLA and omega-3 fats. Eat meat in small amounts (2-4 oz.) no more than once a day. And avoid frying, grilling, or overcooking it, to lessen the formation of carcinogenic compounds.

7. Peanuts. 

For those of us who adore peanut butter, recent controversies surrounding peanuts are troubling indeed. Peanuts are high in protein and rich in heart-healthy monounsaturated fats, but they’re also a common allergen and are heavily sprayed with pesticides. Even organic peanuts have their problems. They’re susceptible to aspergillus, an invisible mold that produces highly carcinogenic compounds called aflatoxins. Because organic peanuts aren’t sprayed with fungicides, they’re even more likely to have aflatoxins than conventional varieties.

The bottom line: If you do eat peanuts, buy them from a store that has a high bulk bin turnover (aflatoxins develop mainly during storage). Or buy vacuum-packed varieties to lessen the amount of exposure the nuts have had to air. Some peanut butters test their products for toxins; Once Again Nut Butter tests each batch for both aflatoxins and salmonella.

8. Nightshades. 

Tomatoes, potatoes, eggplant, peppers, goji berries, belladonna, and pansies are members of the solanaceae family. Known as nightshades, some of them are high in a compound called solanine that can aggravate inflammation in sensitive people-generally, those with arthritis, gout, and other joint problems. It’s also said that nightshades can aggravate everything from migraines to multiple sclerosis. But while solanine is irritating to sensitive people, not all nightshades contain appreciable amounts. It’s most prevalent in potatoes with green areas, unripe tomatoes, and green bell peppers. (Sweet potatoes are from an entirely different family, and contain no solanine.) And because some of the healthiest foods (such as tomatoes and red peppers) are considered nightshades, it’s difficult to justify eliminating them from most diets.

Question, I’ve heard the term “nightshade foods,” but I don’t know what foods those are. I’ve also heard that some people avoid them. Why?

The bottom line: If you have arthritis, joint pain, or a chronic inflammatory condition, try cutting nightshades out of your diet for a week to 10 days, and see how you feel. If your symptoms improve, you may be sensitive to solanine. If you don’t suffer from any of these conditions, you can probably eat tomatoes, peppers, and other nightshades freely. Just be cautious with white potatoes.