Chapter 94
Food for Hearing
The reason scientists assumed that the key to the Mabaan’s good hearing was their diet was that there was also no coronary heart disease in the tribe. What mainly kills us in the industrialized world doesn’t affect them at all. Their blood pressure is perfect their whole lives; even past age 70 it is 110/70, whereas the rest of us, on average, develop high blood pressure starting at 40. That’s no surprise. The Mabaan eat mostly whole grains (sorghum) and “almost no animal protein.” Therefore, the researchers considered the possibility that atherosclerosis, which clogs the small blood vessels in the inner ear, could underlie hearing loss everywhere else in the world.
In fact, healthier food is associated with a significantly lower risk of hearing loss, and on all three scales used to assess diet, meatless eating brought a lower risk. In addition, the Mabaan don’t eat sugary junk, which is why they have virtually no cavities. A high-glycemic diet with refined carbohydrates is also associated with age-related hearing loss, and high blood sugar levels in general may explain why people with diabetes and prediabetes are also at risk. Even compared to other grains, sorghum has a particularly low glycemic index thanks to its abundant resistant starch and causes a 25 percent lower blood sugar response than whole wheat.
How noise damages the inner ear could also be explained by impaired blood flow, because loud sounds cause constriction of the blood vessels at the auditory nerves. That would also explain the association between obesity and hearing loss. Excess weight may just be a sign of unhealthy eating, but pro-inflammatory obesity itself can result in vascular dysfunction. Markers of systemic inflammation appear to be directly proportional to age-related hearing loss, as do markers of oxidative stress.
Details on this in see.nf/earfoods, but fundamentally, one can say: In rats, blueberries reverse hearing deficits; antioxidants in their feed or water prevent age-related hearing loss; in humans, however, antioxidant supplements could not improve hearing. What did help was added folic acid; the healthiest source of it is leafy greens and legumes. (Just 1 cup of cooked lentils contains 90 percent of an adult’s daily requirement, and 1 cup of edamame beans 120 percent.)
What you should avoid if you want to slow hearing loss
In 2021, a large-scale review of the role of nutrition in the development and prevention of age-related hearing loss examined thousands of studies and concluded: “A diet high in saturated fats and cholesterol damages hearing, which could be prevented by reducing consumption.” The story of the Mabaan tribe is of course fascinating, but how do the review’s authors justify their conclusion? True, it can be demonstrated in laboratory animals—if rats are randomized to be fed extra saturated fats and chinchillas cholesterol, scientists can show that an atherosclerosis-promoting diet can worsen inner ear damage and hearing loss—but that does not mean it applies to humans.
For that, there are compelling epidemiological data. For example, a study of thousands of twins found a significant link between a cholesterol-rich diet and impaired hearing. In the Blue Mountains Hearing Study, which included thousands of older men and women, cholesterol was the nutrient most often associated with age-related hearing loss. Those who consumed per day approximately the amount of cholesterol equivalent to 2 eggs were 34 percent more likely to be hard of hearing than someone who ate only the equivalent of 1 egg. Supporting a vascular cause is the fact that people taking statins, especially at higher doses, seemed to have a lower risk. The researchers suspected that the increase in atherosclerotic inflammation in the tiny inner-ear arteries, caused by highly cholesterol-containing food, supports their findings, but why not take a proper look at these arteries to see if that’s true?
The extent and severity of coronary heart disease, as read on an angiogram, are directly proportional to hearing loss. Atherosclerosis is a systemic disease that affects the entire arterial tree, so it also affects the arteries that supply the inner ear. The same connection was found with the amount of deposits in the carotid artery. The more such plaques, the worse the hearing and the greater the risk of further hearing loss over the next 5 years. Now we’re getting closer, but what about the blood vessels that supply the inner ear directly? Data from early autopsies suggest—and direct imaging studies show—that there is a direct relationship between the degree of hearing loss and atherosclerotic narrowing of blood vessels.
Now we still need an intervention study to tie everything together. Yes, a diet high in cholesterol and high in saturated fat has been proven to kill cochlear sensory hair cells in laboratory animals, damaging the inner ear and hearing, but after all, you can’t lock up hundreds of people for a few years and force them to eat different amounts of saturated fat and then see what happens to their hearing. Yes, you can, and that’s been done. Enter: the Finnish Mental Hospital Study. In 1958, one of the two psychiatric institutions near Helsinki changed its menu so that patients were given less saturated animal fat. After a few years, the hospitals then switched menus. That was one of the first intervention studies of its kind, and it showed that you can reduce deaths from heart disease by cutting down saturated fat intake. And the patients’ hearing? It followed exactly the same pattern. To the extent that their heart disease worsened, so did their hearing. And after the hospitals switched their food offerings, the opposite effect occurred—and not just a little. The patients between 50 and 60 in the hospital with reduced saturated fat eventually heard significantly better than patients from the control hospital who were 10 years younger. The researchers noted that “our audiological studies lead us to the conclusion that diet is an important factor in the prevention of hearing loss.”
Preserving the Hormones
The search for a hormonal fountain of youth has a history as colorful as it is controversial. Sigmund Freud recommended to the mother of Prince Philip, Duke of Edinburgh, a strong X-ray irradiation of the ovaries to regain her youthful vitality during perimenopause. In the 1920s and 1930s, this treatment was considered a proven energy-boosting “cure” for aging symptoms in women. Mental and physical disabilities in men were attributed to “loss of semen” through masturbation, and when it was concluded that injecting older men with sperm was too dangerous, a respected physiologist used the “juice” from freshly crushed dog testicles instead. This ultimately led to a trend of transplanting testicular extracts, minced tissue, or whole testicles from billy goats, guinea pigs, or chimpanzees in order to “rejuvenate” aging men. By 1940, more than 10 000 testicular implantations had been performed on human subjects in San Quentin Prison in California.
“Anti-Aging” Hormones
Millions of dollars are spent on hormone treatments in the hope of slowing the aging process, but they may do more harm than good.
Human Growth Hormone
Among all the clinical anti-aging swindles and rip-offs, the sale and use of human growth hormones are “perhaps the most brazen organized form of quackery of our time.” As you will see in detail at see.nf/hgh, there is not only no evidence for these anti-aging effects—on the contrary, growth hormone actually promotes the aging process. Add to that the cancer risk and the risk of a shortened life span, which led one well-known physician to comment that growth hormones could turn out to be a “true anti-aging agent” because they keep you from getting old.
Tired from “Adrenal Fatigue” Syndrome
Many who seek help for general nonspecific complaints are led to believe they suffer from some kind of hormone deficiency. “Adrenal fatigue” is the prime example. The term for this made-up disease was coined in 1998 by a chiropractor and then eagerly adopted by naturopaths and functional and anti-aging physicians, but the title of a systematic review in an endocrinology specialty journal says it all: “Adrenal fatigue does not exist.” At see.nf/adrenal I devote myself to this topic in detail. In short, hawking tests and treatments for a made-up disease without any scientific basis could delay the diagnosis and treatment of a real disease.