These 6 healthy foods are very unhealthy in high doses

One would think, as research on diet and health continues to pile up, we might start inching toward consensus about what is good to eat, and what isn’t. But in many cases the opposite is happening. We can’t even agree on the essential goodness or badness of basic food elements like fat or carbohydrates, with each side enjoying an all-you-can-eat buffet of studies to back up its case. When you factor in other considerations, like the environmental, social and other moral impacts of various foods, things get even more complicated. A recent Washingon Post column even argued against the nutritional and environmental benefits of salad.

Everyone but the junk food industry and sugar producers can at least agree that we need to limit our sugar intake, but there are some other foods, many of which are widely perceived as healthy, that we should ease up on as well. Of course, too much of anything can kill you (even water—water intoxication, aka hyponatremia, is a real, and really serious condition). But there are also some foods of which even a modest amount, consumed on a regular basis, can hurt you. These effects range from relatively benign—too many tomatoes or citrus can give you heartburn, too many carrots can actually impart an orange hue—to more serious: more than three Brazil nuts in a day, for example, can lead to dangerous levels of selenium, over the long haul.

So here is a list of foods you might want to approach with a healthy level of fear. Unlike Brazil nuts, these are foods you might consume on a regular basis, and unlike carrots, they have consequences beyond the cosmetic. And unlike sugar, these foods are widely perceived as healthy.

1. Milk

Nature’s most perfect food is not as perfect as we once thought. When you think about it, we are the only species that drinks milk into adulthood, which at the very least is weird. But more concerning is a large study conducted in Sweden last year that involved nearly 100,000 middle-aged people who’d previously filled out dietary questionnaires for other research projects. High milk consumption did not result in lower rates of broken bones and osteoporosis, as expected. Instead, the study found the opposite: increased milk consumption appeared to make people more susceptible to broken bones. It also appeared to make them more likely to die earlier. As shocking as these results are, since the data was collected for other purposes, some scientists (and of course dairy industry lobbyists) are cautioning that more studies are needed before it becomes abundantly clear that we need to wean ourselves off of bovine mammary secretions altogether.

2. Dried fruit (that isn’t homemade or organic)

Most mass-produced dried fruits contain two concerning additives: sulfite preservatives and added sugar. Enough has been written about the dangers of added sugar, but I do want to point out how insane it is to add sugar to something that is already naturally so sweet. It speaks to how dangerously sweet in the tooth our culture has become. More concerning still, dried fruits have some of the highest sulfite concentrations of all foods, from 500-2,000 parts per million (wine by contrast contains between 20-350 ppm). Sulfites are suspected to contribute to a number of chronic respiratory and neurological conditions, including ALS. Organic dried fruits are free of sulfites, but may still contain organic added sugars. The best way to get your dried fruit on is to make it yourself from fruit that is in season and cheap, or perhaps even free if you know where the unpicked fruit trees are in your neighborhood. Home-dehydrated fruits might not look as bright as their treated counterparts, and you might have to store them in the freezer if you like them chewy. But nothing beats a handful of home-dried fruit when you’re out on the trail, or just hankering for a snack.

3. Beans

​ Their toxicity varies by variety. At the low end of the spectrum, any beans that make you fart are at least presenting a minor problem for your digestive system (not to mention friends and family). But kidney beans and some species of lima beans are very high in phytohaemagglutinin, which is present at some level in most legumes. The good news is, 10 minutes in boiling water can deactivate this toxin. The bad news is, it’s not uncommon for people to soak beans and then add them to a salad, or cook them for hours in a crockpot at lower than boiling temperatures. According to FDA, as few as five undercooked kidney beans can cause symptoms, which include belly pain, vomiting, diarrhea, and other symptoms of severe gastrointestinal distress. Legumes also contain a long list of anti-nutrients, so-called because they can impair the body’s ability to properly digest them and extract their full nutrient value (some of which gets turned into the legendary flatulance). In addition to the phytohaemagglutinin, which is a type of lectin, these antinutrients also include saponins, phytate, polyphenols (tannins, isoflavones), protease inhibitors, raffinose oligosaccharides, cyanogenetic glycosides, and favism glycosides. Their relative contents vary by species. Some, like saponins, are not destroyed by cooking, though some processes such as fermentation (think miso) can convert legumes to a much healthier form.

4. Spinach and parsley?!?!?

If you have kidney issues, yes. And you can add strawberries, star fruit, beets, rhubarb, chard, and those pesky beans to this list as well. All of these foods are high in oxalates, which can build up in your kidneys and crystallize into stones, which are dangerous and painful to eliminate.

5. Pretty much anything from China

China’s air pollution is so bad that respiratory distress is one of the nation’s biggest killers, responsible for 17 percent of deaths in China according to one recent study. That pollution includes a lot of airborne heavy metals, which contaminate the dirt and water used to grow plants, even plants that are grown organically. (And regulation, or lack thereof, of organic standards in China is a whole other story.)

6. Soy sauce (and other forms of salt)

Speaking of China, one of its more popular condiments can be deadly if consumed in enough quantity, and suicide by soy sauce is actually a thing in Asia. Perhaps it belongs in the “enough of anything can kill you” category, but it takes a lot less soy sauce to poison you than water. One 19-year-old American almost made it onto the Darwin Awards short list when he drank a quart of soy sauce on a dare, and woke up convulsing in the emergency room with acute salt toxicity. But the real threat is to babies and small children, who could be harmed by a much smaller dose. A gram of salt per kilogram of body weight can be lethal. A tablespoon contains about 20 grams, and that bottle of soy sauce contains 170 grams of salt, which put the fellow who drank it at just under 2 grams per/kg. He lived to tell the tale, but I don’t think he’ll be doing that again.