Chapter 89
Low-Carb Diets Shorten Life
Those who eat a predominantly plant-based diet have a lower risk of cardiovascular disease and the prospect of a longer life, whereas those who eat few carbohydrates (low-carb diets) suffer far more often from cardiovascular diseases and live shorter lives—their all-cause mortality increases by 22 percent. The side effects of a low-carbohydrate ketogenic diet therefore include—as a review recently listed—not only “chronic fatigue, nausea, headaches, hair loss, decreased alcohol tolerance, reduced physical performance, heart palpitations, leg cramps, a dry mouth, a bad taste in the mouth, bad breath, gout, or constipation,” but also premature death.
Studies found that low-carbohydrate eating worsens heart disease and impairs arterial function. Arterial function is significantly impaired three hours after a meal high in saturated fat, even when it comes from plant sources such as coconut oil. On a ketogenic diet, arterial function worsens even after a weight loss of twelve pounds, apparently generally with low-carbohydrate eating.
A low-carb diet is also associated with a significantly higher risk of death from cancer. That could be due to the greater amount of IGF-1 in the body, induced by the animal proteins one consumes (see the IGF-1 chapter), or due to the increased amounts of industrial toxins one eats. 90 percent of the ongoing intake of toxins comes from foods of animal origin, so it is not surprising that with low-carbohydrate and high-protein eating you have larger amounts of contaminants in your blood, for example mercury, lead, PCBs 118 and 153 (polychlorinated biphenyls), DDE (from DDT), trans-nonachlor (a component of the now-banned pesticide chlordane), and hexachlorobenzene (a banned fungicide). The Mediterranean diet has also been linked to higher PCB levels (more precisely PCBs 118, 126, 153, and 209), trans-nonachlor, and mercury, presumably due to fish consumption.
About Fish
In part because of the American Heart Association’s recommendation that people at high risk for heart disease should ask their doctors about omega-3 fish oil supplements, sales of fish oil pills shot up, and a multibillion-dollar industry emerged, but the most comprehensive systematic review of the evidence found that increased intake of fish fats (EPA and DHA) has “little or no effect on mortality and cardiovascular health.” Longevity experiments in mice also found no benefits for the aging process or life span. Where does the idea even come from that omega-3 fats from fish and fish-oil products are something good? I get to the bottom of the whole legend in see.nf/fishoil and discuss details such as contaminants, rancid products, and the five comprehensive published trials with thousands of randomized participants and various fish-oil preparations versus placebo. A fish-oil supplement may at some point have a benefit, but at the moment meta-analyses “clearly show” that over-the-counter fish-oil supplements “offer no benefit” for the cardiovascular system.
Replace the Meat
But what if you just eat fish? In population studies, it is difficult to separate the effect of eating fish from the characteristics of fish eaters. People who eat fish tend to smoke less and exercise more, belong to a higher socioeconomic class, and reach for convenience meals less often, but more often for organic foods; they eat hardly any full-fat dairy products and meat, more vegetables, and fewer sweets. When scientists try to exclude some of these factors, most studies on fish consumption show no association with mortality from cardiovascular diseases.
Still, with nutrition studies you always have to ask the key question: Compared to what? Take the question of whether eggs are healthy. Compared to sausages? Yes. Compared to oatmeal? No. Seen this way, fish and seafood can replace foods that are even unhealthier. Surprisingly, randomized controlled trials show that fish is even more harmful than red meat with respect to LDL cholesterol. Fish is therefore worse than beef, but still better than bacon.
Researchers at Harvard found that processed meat as a protein source was the worst for the risk of premature death, followed by eggs, while plant protein sources performed best. In summary, they found that it is better to eat a tuna salad than an egg salad or a bacon sandwich, but the winner was a bean burrito. For all-cause mortality, plant protein performed better than any form of animal protein—red meat, poultry, fish, dairy products, or eggs. Replacing red meat with white meat, for example poultry and fish, does not significantly lower all-cause mortality, but chickpeas can, for example, if you replace meat with them. Replacing just 3 percent of calories from animal proteins with plant proteins produces a significantly lower overall risk of premature death.
Making It Vanish
Because heart disease is the most likely thing to kill us, our life expectancy mainly depends on it. Bill Castelli, for a long time the director of the world’s longest-running epidemiological study, the famous Framingham Heart Study, was once asked what he would do to reverse the epidemic of coronary disease if he were all-powerful. His answer? “I would get everyone to eat like Dr. T. Colin Campbell.” He told the network PBS that if Americans ate enough plants, the entire heart-disease epidemic would “just disappear.”
Keep Your Hair
In the photos in all my class yearbooks I have a wild mop of hair. No matter what my mother did to tame it, she couldn’t. (I looked casually windblown without having to do anything for it.) Later came my heavy-metal phase, when I needed my long hair for headbanging. Unfortunately, like many men in my family, it quickly became thinner and eventually took its leave. Why do some people lose their hair and others don’t? Why do some go gray earlier than others? How can you keep your curls?
Graying
That hair turns gray is among the most obvious signs of aging. There is a technical term for it that I had never heard: canities. (When I first read the word, I misread it and wondered what gray hair had to do with canines, the canine teeth.) Actually, gray hair is neither gray nor white; rather, the pale yellow tinge of the dominant keratin protein looks, as with polar bears, white when it reflects light.
Why do we go gray?
I discuss the prevailing “free radical theory of graying” in see.nf/gray. It is mainly about the fact that the free radicals that naturally arise during pigment production lead to the death of pigment-producing cells because antioxidant defenses decline with age.
Reversible and contributing reasons
Age-related “exhaustion of pigment potential” is considered largely genetic; up to 90 percent familial. But if the speed of graying is determined by oxidative damage, what role do antioxidants and systemic oxidative stress outside the hair follicles play? Those who go gray prematurely appear to have higher markers of oxidative damage and fewer antioxidants in the blood. The fact that smokers tend to go gray earlier supports the suspicion that external free radicals accelerate oxidation in the aging hair follicle. Obese people tend to go gray earlier, which fits the concept of oxidative stress, even though that is not the case for people who drink alcohol. Alcohol unquestionably triggers oxidative stress, but is not significantly associated with premature graying.
Anyone who tries to optimize antioxidant intake by eating a predominantly plant-based diet has to learn to deal with the Achilles’ heel—the risk of vitamin B12 deficiency if you do not actively counter it with B12 supplements or fortified foods. A B12 deficiency is among the few reversible causes of graying, even though we do not know the mechanism. Fortunately, hair regains its old color once you have enough B12 in your body again. Another reversible cause is hypothyroidism, which can be treated with hormone replacement therapy.
Enough about oxidative stress—what about ordinary stress? In see.nf/hairstress I address the question of whether the fight-or-flight response can turn hair white, why we go gray at all, and whether premature or excessive graying is a sign of accelerated aging and the risk of age-related diseases.