Vegetables for the Gums

A few plants—namely leafy and root vegetables—have another secret weapon: nitrates. Not only do they improve circulation, but they also have antimicrobial effects in saliva, as shown in a randomized placebo-controlled double-blind trial for relieving gingivitis. You can get the whole story in see.nf/chewing.

Sense and Nonsense of Oil Pulling

You can safely smear coconut oil into your hair and on your skin, but according to the American Heart Association and the American College of Cardiology, it’s better not to eat it. Really, you shouldn’t even be in the kitchen where coconut oil is being heated. No idea how anyone got the idea it was good for cooking. Coconut oil smokes even at low temperature and gives off lots of toxins at normal frying temperature. But what if you just hold it in your mouth and swish it around?

I made a four-part video series, starting with see.nf/oilpulling, about a traditional healing method in which oil is “pulled” back and forth through the teeth for minutes before spitting it out, and it is then supposed to “contribute to oral and systemic health.” But there is no evidence of a systemic healing effect, and the impacts on oral health are assessed inconsistently (good, bad, and neutral). The reason you should never do it is the very real danger of lipoid pneumonia, a possible consequence if you inhale small amounts of an oily substance into the lungs. In fact, the studies on it were conducted on “a collection of extracted human teeth”—sounds like a horror movie—and not on living subjects, because the researchers believed it would be “ethically unjustifiable to test oil pulling in humans, because it is known that it can cause lipoid pneumonia in volunteer subjects.”

Don’t Be Sour at the End

A meta-analysis of 18 studies on the effects of vegetarian diets on oral health found that vegetarians have significantly fewer decayed or missing teeth or dental fillings. That’s not surprising, considering that vegetarians eat more antioxidants and anti-inflammatory foods. People who eat plant-based also have had significantly less oral cancer in every study to date on this subject, which is why an article in the Journal of the American Dental Association concluded: “The results support the recommendation to eat plenty of fresh fruits and vegetables as part of a whole-food, plant-based diet.” Vegetarians do seem to have one weak point, though: an increased risk of enamel erosion, presumably due to acidic fruits and vegetables such as citrus fruits and tomatoes.

The solution, which I also explain in see.nf/sour, is to rinse your mouth with water after consuming acidic foods or drinks and to wait at least 30, preferably 60 minutes before brushing your teeth, so the teeth can remineralize and are not brushed while in a softened state.

Is Fluoride Safe and Effective?

One of the studies ran counter to the trend and showed that vegetarians had more cavities; it attributed the excessive damage to the fact that vegetarians are significantly less likely to use fluoride toothpaste, which has been proven to reduce cavities. Adding fluoride to drinking water is rather controversial. Health authorities have described it as one of the ten greatest public health achievements of the 20th century, but the growing body of evidence for fluoride’s negative effects on brain development ultimately prompted the National Toxicology Program to assess that fluoride must now “be regarded as a hazard to human cognitive development.”

Until now, fluoride opponents had been accused of being “anti-science,” but now, ironically, proponents of fluoridation may be ignoring evidence that does not fit their beliefs. How can society enjoy fluoride’s benefits in preventing cavities without the risks? Since the main risk is systemic absorption into the body, but the main benefit is contact with tooth enamel, you could safely secure the benefits by using fluoride toothpastes and mouth rinses. Why I changed my mind about drinking-water fluoridation, I explain in my five-part video series that begins with see.nf/fluoride.

Preserving Vision

More than a million Americans are officially blind. The good news is that a healthy diet can prevent the four most common causes of vision loss: macular degeneration, diabetic retinopathy, glaucomas, and cataracts.

Macular Degeneration

Age-related macular degeneration is the leading cause of blindness in industrialized countries. The macula is the central spot of sharpest vision on the retina at the back of the eye. What can cause it to degenerate?

The retina, the inner lining at the back of the eyeball, converts light into vision. This continuous output requires enormous amounts of oxygen and energy, making the retina one of the most metabolically active tissues in the body—adjusted for its weight, it even consumes more than the brain. Added to the oxidative stress that arises from this high-powered operation are the free radicals generated by sunlight, because those are focused directly onto the macula like through a magnifying glass. This cumulative oxidative burden is thought to be decisive for age-related macular degeneration.

In eyes that people donated to science after their death, those with age-related macular degeneration had more oxidative stress and DNA damage from free radicals than eyes without macular degeneration. Even in the blood of people with age-related macular degeneration, you find more oxidative damage, an indication that the antioxidant defense system has broken down. The pro-oxidants in cigarette smoke could explain why smokers have a fourfold greater risk for this disease. To slow the progression of macular degeneration, smoking patients should absolutely quit smoking and add to their diet a special mixture of antioxidant pigments that go directly into the macula.

The technical term for the macula is macula lutea, from the Latin macula, “spot,” and lutea, “yellow.” That’s what it is, because when we doctors look at the back of your eye with a bright light, it is yellow. The color comes from two yellow plant pigments that concentrate in the macula like a laser beam and reach a density there 1000 times higher than in other tissues. Just one or two millimeters next to the fovea, the concentration already drops by a factor of 100. The body knows exactly where to send the pigment. The two most important pigments, lutein and zeaxanthin, absorb blue light and thereby protect the retina from photo-oxidative damage.

The yellowing of the lens when you develop a cataract could be a mechanism of the body to defend the retina. In fact, the risk of going blind from macular degeneration after cataract surgery rises because you remove that protection. Instead of trading one kind of blindness for another, it would be better to pigment the back of the eye through diet and not the front of the eyes through cataracts. The pigments in the back of the eye come exclusively from the diet.