Preventing Toenail Fungus

First comes the pathogen. Here it is mainly the one that also causes jock itch, ringworm, and athlete’s foot. You can prevent your feet from becoming a fungal depot by keeping them clean and dry. You can prevent fungi from penetrating the nail by using only disinfected instruments for nail care. You also shouldn’t share your nail polish with anyone, because the fungus can survive in it for months. Artificial nails endanger fingernails because the acrylic traps moisture that otherwise would have evaporated through the nail. (Nails contain little fat and are therefore 1000 times more water-permeable than skin.)

Then comes the host. Fungal nail infections can be the result of poor blood flow to the arms and legs, which otherwise would enable the body’s own defenses to keep the fungus at bay. A study with 400 participants found that circulation in patients with athlete’s foot and nail fungus was more than 50 percent lower than in subjects without a fungal disease. Fungal nail infections may therefore be only symptoms of a deeper problem, such as weakened immune defenses or poor circulation; for that reason, complete elimination of these infections may be “unrealistic.” That led to a fatalistic response: “A more appropriate goal would be relief of symptoms …” But if circulation is a problem, why not try to improve it?

Thanks to one of the first studies on reversing cardiovascular disease ever published, we have known since the 1950s that blood flow in the peripheral arteries can be turned on and off within a few days like a switch, simply by alternating back and forth between the conventional diet that caused the problem in the first place and a low-fat plant-based diet.

Separation anxiety

Many over-the-counter products allegedly improve nail quality, but little evidence supports these claims, and sometimes the products even make everything worse. The cuticle serves a purpose. It forms a barrier against pathogens and should be left alone, not cut or pushed back. You shouldn’t file the surface of the nail, because doing so makes nails thinner and more likely to break; you shouldn’t stick sharp objects under the nail, because they can pierce the nail fold, which protects the nail bed from infection, and then there is the risk of a partial separation of the nail from the nail bed (onycholysis).

Acrylic nails can also promote onycholysis if the adhesive is stronger than the natural bond between the nail and nail bed. Moisture that collects under artificial nails promotes separation of the nail. Nail hardeners can be a cause of nail separation, because they contain up to 5 percent formaldehyde (also listed on the label as “formalin” or “methylene glycol”), which can trigger inflammation.

Preventing brittle nails

One in five people has brittle nails, women twice as often as men. Confirmed risk factors include dehydration, certain chemicals, and injuries. It is commonly said that nail hardness depends on the nail’s supply of fluid. Nails would become soft if they got too much fluid and brittle if they dried out; therefore, it is often recommended to soak the nails daily and use nail creams, oils, or salves. When this assumption was tested, however, it turned out that the water content of brittle fingernails was not significantly different from that of normal fingernails. In fact, the brittle nails contained a little more water. At least one factor was found that triples the risk for brittle nails: professional manicures.

But couldn’t people with brittle nails be more likely to go for manicures, rather than manicures leading to brittle nails? Nail cosmetics, including nail polish remover, solvents, nail hardeners, cuticle removers, and premixed acrylic gels, as well as applying nail wraps or nail extensions, can weaken the nail structure. You would think nail hardeners would help, but in the long run their formaldehyde may do more harm than good.

At home, you should use acetone-free nail polish remover (for example acetate) and use it at most once a week, because it is one of the main causes of brittle nails. Artificial nails can protect brittle nails, but when you remove them, the nail is always injured, and if you use them for a long time, that can reduce oxygen transport to the nail and weaken the nail. Finally, you should not file the nail surface or subject the nails to repeated stress such as typing.

Biotin for brittle nails?

Biotin is popular as a remedy for nail growth, but also for hair growth—and there biotin was a total flop. Is it the same with biotin and nails? We don’t know exactly, because apparently not a single placebo-controlled study on the topic has been published.

How did anyone even get the idea that biotin could help? Severe biotin deficiency is associated with weak nails, but that probably affects only people who eat raw egg whites. In ponies, biotin speeds the growth of hoof horn by 15 percent. (Pony hooves are made of the same material as our nails.) So how does biotin work in humans?

There are two uncontrolled before-and-after studies suggesting that 2.5 milligrams of biotin a day could help. One found an increase in nail thickness of 25 percent after 6 to 15 months. But there was also a controlled study. In it, brittle fingernails were treated once a day for four months with a care polish, and in the experimental group an additional 10 milligrams of biotin was taken. In the biotin group, the condition of the nails improved significantly in 80 percent of subjects, compared with only 53 percent in the control group. Unfortunately, biotin at that amount could throw off lab measurements.

Depending on the dose, you should stop the biotin one to five days before a planned blood test, for thyroid values or pregnancy. The FDA was urged to issue a warning after biotin in one case distorted a test result (for troponin), a heart attack went unrecognized, and the patient died. You can’t plan such tests.

A survey of outpatient dermatology patients taking biotin found that only 7 percent had ever heard of this FDA warning, and a nationwide survey of physicians likewise revealed substantial knowledge gaps. 2.5 milligrams a day is probably too little to distort lab results, so biotin may be worth a try for brittle nails, even if there is no solid evidence that it helps.

Preserving the teeth

More than 65 percent of the US population over 65 years of age suffers from periodontitis. The word is composed of the Greek elements para-, “beside,” -odont-, “tooth,” and -itis for “inflammation.” Periodontitis, or periodontal disease, is a disease of the tissue that surrounds and holds the teeth in place, and a main cause of tooth loss.

Oral health problems such as periodontitis and tooth loss are associated with poor diet, and the connection may be bidirectional. Thus, pro-inflammatory foods such as saturated fatty acids contribute directly to tooth loss. Or, with tooth loss, you eat more fatty foods such as processed meat, because it is easier to chew. The same goes for foods associated with less tooth loss—fruits and vegetables—they are anti-inflammatory but also have to be chewed more. Does poor diet lead to bad teeth, or vice versa? Or both?