Part 7: Safety Second — Deficiency
Will a low-carb diet lead to diseases of deficiency? It shouldn’t, because we don’t actually restrict the bulk of fruits and vegetables. Only refined sugar, flour, bread, potatoes, rice, beer, and those foods composed chiefly of these need be restricted.
This leaves a rather large remainder for our nutrition: this week, for example, I’ve had an apple, asparagus, broccoli, carrots, garlic, mushrooms, onions, tomatoes, yellow squash, and zucchini in mass quantities, in addition to copious amounts of delicious meat and cheese.
But what if we did eat only meat? Again, the experiment has already been done, and a long time ago:
In the early 1920s, a Harvard anthropologist-turned-Arctic-explorer named Vilhjalmur Stefansson publicized the idea of a carbohydrate-restricted diet based on fatty meat.
What follows is quite a long quote, but stick with it: I, at least, found it absolutely fascinating.
[Stefansson] was concerned with the overall healthfulness of the diet, rather than its potential for weight loss. [He] had spent a decade eating nothing but meat among the Inuit of northern Canada and Alaska. The Inuit, he insisted, as well as the visiting explorers and traders who lived on this diet, were among the healthiest if not the most vigorous populations imaginable.
…The ability to thrive on such a vegetable- and fruit-free diet was also noted by the lawyer and abolitionist Richard Henry Dana, Jr., in his 1840 memoirs of life on a sailing ship, Two Years Before the Mast. For sixteen months, Dana wrote, “we lived upon almost nothing but fresh beef; fried beefsteaks, three times a day…[in] perfect health, and without ailings and failings.”
…None of Stefansson’s findings would have been controversial had not the conventional wisdom been — as it still is — that a varied diet is essential for good health.
…This philosophy, however, was based almost exclusively on studies of deficiency diseases, all of which were induced by diets high in refined carbohydrates and low in meat, fish, eggs, and diary products. When the Scottish naval surgeon James Lind demonstrated in 1753 that scurvy could be prevented and cured by the consumption of citrus juice, for example, he did so with British sailors who had been eating the typical naval fare “of water gruel sweetened with sugar in the morning, fresh mutton broth, light puddings, boiled biscuit with sugar, barley and raisins, rice and currants.” Pellagra was associated almost exclusively with corn-rich diets, and beriberi with the eating of white rice rather than brown.
…What nutritionists of the 1920s and 1930s didn’t then know is that animal foods contain all of the essential amino acids (the basic structural building blocks of proteins), and they do so in the ratios that maximize their utility to humans. They also contain twelve of the thirteen essential vitamins in large quantities.
…The thirteenth vitamin, vitamin C, ascorbic acid, has long been the point of contention. It is contained in animal foods in such small quantities that nutritionists have considered it insufficient and the question is whether this quantity is indeed sufficient for good health.
…the dangers of an all-meat diet were considered sufficiently likely that even Francis Benedict, as Stefansson told it, claimed that it was “easier to believe” that Stefansson and all the various members of his expeditions “were lying, than to concede that [they] had remained in good health for several years on an exclusive meat regimen.”
In the winter of 1928, Stefansson and Karsten Anderson, a thirty-eight-year-old Danish explorer, became the subjects in a yearlong experiment that was intended to settle the meat-diet controversy. The experiment was planned and supervised by a committee of a dozen respected nutritionists, anthropologists, and physicians. Eugene Du Bois and ten of his colleagues from Cornell and the Russell Sage Institute of Pathology would oversee the day-to-day details of the experiment.
For three weeks, Stefansson and Anderson were fed a typical mixed diet of fruits, cereals, vegetables, and meat while being subjected to a battery of tests and examinations. Then they began living exclusively on meat, at which point they moved into Bellevue Hospital in New York and were put under twenty-four-hour observation. Stefansson remained at Bellevue for three weeks, Anderson for thirteen weeks. After they were released, they continued to eat only meat for the remainder of one year. If they cheated on the diet, according to Du Bois, the experimenters would know it from regular examinations of Stefansson’s and Anderson’s urine. “In every individual specimen of urine which was tested during the intervals when they were living at home,” Du Bois wrote, “acetone [ketone] bodies were present in amounts so constant that fluctuations in the carbohydrate intake were practically ruled out.”
The experimental diet included many types of meat… Stefansson and Anderson each consumed an average of almost two pounds of meat per day, or 2,600 calories: 79 percent from fat, 19 percent protein, and roughly 2 percent from carbohydrates (a maximum of 50 calories a day), which came from glycogen contained in the muscle meat…
“The only dramatic part of the study was the surprisingly undramatic nature of the findings,” wrote Du Bois, when he later summarized the results. “Both men were in good physical condition at the end of the observation,” he reported in 1930, in one of the nine article he and his colleagues published on the study. “there was no subjective or objective evidence of any loss of physical or mental vigor.” Stefansson lost six pounds over the course of the year, and Anderson three, even though “the men led somewhat sedentary lives.” Anderson’s blood pressure dropped from 140/80 to 120/80; Stefansson’s remained low (105/70) throughout. The researchers detected no evidence of kidney damage or diminished function, and “vitamin deficiencies did not appear.” Nor did mineral deficiencies, although the diet contained only a quarter of the calcium usually found in mixed diets, and the acidic nature of a meat-rich diet was supposed to increase calcium excretion and so deplete the body of calcium. Among the minor health issues reported by Du Bois and his colleagues was the observation that Stefansson began the experiment with mild gingivitis (inflammation of the gums), but this “cleared up entirely, after the meat diet was taken.”
…Nutritionists would establish by the late 1930s that B vitamins are depleted from the body by the ocnsumption of carbohydrates. “There is an increased need for these virtamins when more carbohyrdrate in the diet is consumed,” as Theodore Van Itallie of Columbia University testified t the McGovern’s Select Committee in 1973. A similar argument can now be made for vitamin C. Type 2 diabetics have roughly 30 percent lower levels of vitamin C in their circulation than do nondiabetics. Metabolic syndrome is also associated with “significantly” reduced levels of circulating vitamin C, which suggests that vitamin-C deficiency might be another disorder of civilization. One explanation for these observations — described in 1997 by the nutritionists Julie Will and Tim Byers, of the Centers for Disease Control and the University of Colorado respectively, as both “biologically plausible and empirically evident’ — is that high blood sugar and/or high levels of insulin work to increase the body’s requirements for vitamin C.
The vitamin-C molecule is similar in configuration to glucose and other sugars in the body. It is shuttled from the bloodstream into the cells by the same insulin-dependent transport system used by glucose. Glucose and vitamin C compete in the cellular-update process, like strangers trying to flag down the same taxicab simultaneously. Because glucose is greatly favored in the contest, the uptake of vitamin C by cells is “globally inhibited” when blood-sugar levels are elevated. In effect, glucose regulates how much vitamin C is taken up by the cells…if we increase blood-sugar levels, the cellular uptake of vitamin C will drop accordingly. Glucose also impairs the reabsorption of vitamin C by the kidney, and so, the higher the blood sugar, the more vitamin C will be lost in the urine. Infusing insulin into experimental subjects has been shown to cause a “marked fall” in vitamin-C levels in the circulation.
In other words, there is significant reason to believe that the key factor determining the level of vitamin C in our cells and tissues in not how much or little we happen to be consuming in our diet, but whether the starches and refined carbohydrates in our diet serve to flush vitamin C out of our system, while simultaneously inhibiting the use of what vitamin C we do have.
…from Good Calories, Bad Calories (Knopf, 2007), by Gary Taubes, p. 320-326
Continued in Part Eight…