Vitamin supplements have been around since the 1930s. Their popularity exploded in the wake of the 1970 best-selling book Vitamin C and the Common Cold, by renowned chemist and Nobel laureate Linus Pauling, who claimed, without adequate evidence, that vitamin C could prevent colds, and even cancer. Pauling’s prestige started a fad that never ended.
As of 2016, the worldwide market for dietary supplements was (US) $133 billion. Consumers consider such supplements a hedge against nutritional deficiencies in their diet.
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One crucial aspect of vitamin quality is bioavailability: effectively passing into the bloodstream versus uselessly passing through the body. Befitting capitalist exploitation, manufacturers commonly skimp on quality to gull unsuspecting consumers.
Magnesium oxide is 1/10th as bioavailable as magnesium aspartate. Despite this, vitamin makers frequently use the oxide form, because aspartate is more expensive and bulkier. And – bioavailability be damned – the listed amount of magnesium on the label is the same.
Another quality aspect is adulteration. Cheap vitamins, and other supplements, typically have low-quality ingredients, and incidental unsanitary filler. Under capitalism you get what you pay for (at least sometimes on the high end).
Vitamins are best taken with food to increase their potential absorption. Fat-soluble vitamins should be taken once a day at most, but once or twice a week is best. As water-soluble vitamins quickly pass through, they may be taken once a day.
Weight loss and bodybuilding supplements are nothing short of dangerous, especially protein supplements. In the United States alone, ~50,000 adverse reactions to dietary supplements occur every year.
No consumer can ever know what’s inside a bottle. ~ American physician Amy Eichner
FDA allowance is a declaration of ignorance. The agency itself admits its impotence:
Remember, FDA cannot test all products on the market that contain potentially harmful hidden ingredients. Enforcement actions and consumer advisories for tainted products only cover a small fraction of the tainted over-the-counter products on the market. ~ US Food and Drug Administration
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Processed foods are attractive because they are cheaper, highly palatable due to high sugar, salt, and saturated fat content, are widely available, highly marketed, ready to eat, and their use-by dates are lengthy, so they last longer. ~ Indian-British epidemiologist Nita Forouhi
Processed food is essentially a gambit of convenience. Commercial processing invariably reduces nutritional content while often introducing chemicals of problematic benefit.
There is a growing body of evidence on the health harms of processed foods. ~ Nita Forouhi
What a food is and how it metabolizes are two very different things. The biochemical reductionist approach to nutrition can only yield definitive answers that are offbase.
Nutrition is complex. ~ American epidemiologist Susan Mayne
Nutrition cannot be understood from a test tube. Yet relying on test-tube science has been a ubiquitous approach to nutrition research, as it may conveniently be carried out in a lab.
Observations on segments of the population over time may seem a good metric, but there are too many variables to draw any conclusions with confidence.
Every person has about 50,000 variations in their genes. ~ American nutritionist Steven Zeisel
The ability to estimate population trends in caloric intake and generate empirically supported public policy relevant to diet-health relationships from US nutritional surveillance is extremely limited. ~ American epidemiologist Steven Blair et al
The trials we have in nutrition aren’t answering the right questions, so they’re not appropriate. What we’re using now is pretty bad science. ~ American nutritionist Connie Weaver
Despite inherent uncertainties, opinions can be resolute.
We believe that the case is closed – supplementing the diet of well-nourished adults with (most) mineral or vitamin supplements has no clear benefit and might even be harmful. These vitamins should not be used for chronic disease prevention. Enough is enough. ~ epidemiologists Eliseo Guallar, Saverio Stranges, and Lawrence Appel, physician Cynthia Mulrow, and medical researcher Edgar Miller
The above quote contains a crucial assumption – “well-nourished adults” – by which the conclusion falters. The study which drew the above tart remark prompted the following condemnation:
I just felt sadness that such a poorly done paper would be published in a prominent journal and cause so much confusion. ~ American epidemiologist Meir Stampfer
Such is the state of nutritional research.