Isegoria

Is NAC an undetectable athletic performance enhancer?

N-acetylcysteine (NAC) has been extensively studied, mainly for its ability to replenish levels of intracellular glutathione, the body’s “master antioxidant”, probably more important than any antioxidant that can be ingested in food. NAC does this by supplying cysteine, an amino acid which is the rate-limiting constituent in glutathione biosynthesis. Cysteine is normally present in protein-rich foods, especially animal proteins, but it is in both short supply when one wants glutathione levels to increase, and it can’t be taken separately, since it can be toxic and won’t properly enter the cells where it’s needed either. NAC overcomes both of these problems: it’s relatively non-toxic, and is taken up by cells and de-acetylated to form cysteine, which can then be used in glutathione synthesis.

Depletion of glutathione levels is a cause, an indicator, or both, of fatigue due to exercise. It’s been shown clinically that administration of NAC does indeed raise glutathione levels, and now, it’s been shown that, in trained athletes, NAC increases time to fatigue by an astonishing 23%.

In the cited study, fairly massive amounts of NAC were infused intravenously during exercise, which might lead one to doubt the practicality of using it to enhance athletic performance. However, another study — one of many that could be cited — Effect of N-acetyl-cysteine on the hypoxic ventilatory response and erythropoietin production: linkage between plasma thiol redox state and O2 chemosensitivity, found that very modest doses of NAC, 200 mg three times daily, massively increased erythropoeitin production and increased the hypoxic ventilatory response.

Dr Zane Andrews, a neuroendocrinologist with Monash University‘s Department of Physiology, has discovered that key appetite control cells in the human brain degenerate over time, causing increased hunger and potentially weight-gain as we grow older:

“When the stomach is empty, it triggers the ghrelin hormone that notifies the brain that we are hungry. When we are full, a set of neurons known as POMC’s kick in.

“However, free radicals created naturally in the body attack the POMC neurons. This process causes the neurons to degenerate overtime, affecting our judgement as to when our hunger is satisfied,” Dr Andrews said.

The free radicals also try to attack the hunger neurons, but these are protected by the uncoupling protein 2 (UCP2).
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“A diet rich in carbohydrate and sugar that has become more and more prevalent in modern societies over the last 20-30 years has placed so much strain on our bodies that it’s leading to premature cell deterioration,” Dr Andrews said.

Running ‘can slow ageing process’:

The work tracked 500 older runners for more than 20 years, comparing them to a similar group of non-runners. All were in their 50s at the start of the study.

Nineteen years into the study, 34% of the non-runners had died compared to only 15% of the runners.

Both groups became more disabled with age, but for the runners the onset of disability started later — an average of 16 years later.

The health gap between the runners and non-runners continued to widen even as the subjects entered their ninth decade of life.

Running not only appeared to slow the rate of heart and artery related deaths, but was also associated with fewer early deaths from cancer, neurological disease, infections and other causes.

And there was no evidence that runners were more likely to suffer osteoarthritis or need total knee replacements than non-runners — something scientists have feared.

At the beginning of the study, the runners ran for about four hours a week on average. After 21 years, their weekly running time had reduced to around 76 minutes, but they were still seeing health benefits from taking regular exercise.

Researchers were hoping to deliver exercise in a pill, but instead they produced a performance-enhancing drug:

In 2004, Evans and his colleagues genetically engineered mice by tweaking a gene called PPAR-delta, a master regulator of different genes. Gene-engineered mice could run twice as far as normal mice and stayed lean even when fed a high-fat diet.

The next step was to find a drug that might mimic these effects.

Evans tested a compound called GW1516, one of a family of compounds that researchers are looking at as obesity and diabetes drugs. But even though it affected the genes of the mice, it did not affect their metabolism.

“There was no change at all in running performance. Nothing — not even a percent,” Evans said in a statement.

Then the researchers thought about what happens in real life.

“If you’re out of shape — and most of us are — and you want to change, you have to do some exercise. The way we reprogram muscle in adults is by training.”

So they trained the mice while some were on the drug and others were not.

All the mice became more athletic but those given GW1516 ran 68 percent longer than those that had only done the exercise training. “The dramatic effect of the drug was stunning,” Evans said.

A drug like that doesn’t help couch potatoes, of course, or anyone with, say, a muscle-wasting disease, so they produced another drug along the same lines:

Mice given AICAR ran 44 percent longer than untreated animals, the researchers found.

“This is a drug that is like pharmacological exercise,” Evans says. “After four weeks of receiving the drug, the mice were behaving as if they’d been exercised.”

Treated mice could outrun mice given traditional exercise training, Evans said.

The closer you are to the ball, the higher your score on the Wonderlic IQ test. Ben Fry decided to illustrate this:

Wonderlic himself says that basically, the scores decrease as you move further away from the ball, which is interesting but unsurprising. It’s sort of obvious that a quarterback needs to be on the smarter side, but I was curious to see what this actually looked like. Using this table as a guide, I then grabbed this diagram from Wikipedia showing a typical formation in a football game. I cleaned up the design of the diagram a bit and replaced the positions with their scores….To make the diagram a bit clearer, I scaled each position based on its score….With the proportion, I no longer need the numbers, so I’ve switched back to using the initials for each position’s title:

I’m odd enough that this was one of my first questions:

Don’t tell Tufte that I’ve used the radius, not the proportional area, of the circle as the value for each ellipse! A cardinal sin that I’m using in this case to improve proportion and clarify a point.

(Hat tip to Alex Tabarrok.)

Soy foods 'reduce sperm numbers' — or lesser men eat soy:

The Harvard School of Public Health study looked at the diets of 99 men who had attended a fertility clinic with their partners and provided a semen sample.

The men were divided into four groups depending on how much soy they ate, and when the sperm concentration of men eating the most soy was compared with those eating the least, there was a significant difference.

The “normal” sperm concentration for a man is between 80 and 120 million per millilitre, and the average of men who ate on average a portion of soy-based food every other day was 41 million fewer.

Dr Jorge Chavarro, who led the study, said that chemicals called isoflavones in the soy might be affecting sperm production.

These chemicals can have similar effects to the human hormone oestrogen.

Dr Chavarro noticed that overweight or obese men seemed even more prone to this effect, which may reflect the fact that higher levels of body fat can also lead to increased oestrogen production in men.

In a Swedish study, 55 men were given testosterone injections and then given the standard drug test. Most of the men tested positive, but 17 did not.

Some Athletes’ Genes Help Outwit Doping Test:

Those 17 men can build muscles with testosterone, they respond normally to the hormone, but they are missing both copies of a gene used to convert the testosterone into a form that dissolves in urine. The result is that they may be able to take testosterone with impunity.

The gene deletion is especially common in Asian men, notes Jenny Jakobsson Schulze, a molecular geneticist at the Karolinska University Hospital in Stockholm. Dr. Schulze is the first author of the testosterone study, published recently in The Journal of Clinical Endocrinology and Metabolism.

Dr. Schulze learned from an earlier study that about two-thirds of Asian men are missing both copies of the gene, as are nearly 10 percent of Caucasians. The prevalence in other groups is not known.
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The gene in question adds a chemical, glucuronide, to testosterone. That converts it from a substance that dissolves in oil into one that dissolves in water and urine.
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The men with two normal copies of the gene had T [testosterone] to E [epitestosterone] ratios that soared to 100; those with one copy of the gene had ratios that reached 50; those with no copies had almost no rise in their ratios and 40 percent of them had a ratio that never reached 4.

So the gold medal goes to the guy who’s genetically untestable? Great.

(Hat tip to Educated Guesswork.)

Michael Shermer examines The Doping Dilemma, specifically in cycling, and describes the immense advantage from using recombinant erythropoietin (r-EPO) to stimulate the production of red blood cells:

One of the subtle benefits of r-EPO in a brutal three-week race like the Tour de France is not just boosting HCT levels but keeping them high. Jonathan Vaughters, a former teammate of Armstrong’s, crunched the numbers for me this way: “The big advantage of blood doping is the ability to keep a 44 percent HCT over three weeks.” A “clean” racer who started with a 44 percent HCT, Vaughters noted, would expect to end up at 40 percent after three weeks of racing because of natural blood dilution and the breakdown of red blood cells. “Just stabilizing [your HCT level] at 44 percent is a 10 percent advantage.”

Scientific studies on the effects of performance-enhancing drugs are few in number and are usually conducted on nonathletes or recreational ones, but they are consistent with Vaughters’s assessment. (For obvious reasons, elite athletes who dope are disinclined to disclose their data.) The consensus among the sports physiologists I interviewed is that r-EPO improves performance by at least 5 to 10 percent. When it is mixed in with a brew of other drugs, another 5 to 10 percent boost can be squeezed out of the human engine. In events decided by differences of less than 1 percent, this advantage is colossal.

Hunger can make you happy — or at least motivated:

When our bodies notice we need more calories, levels of a hormone called ghrelin increase. Ghrelin is known to spur hunger, but new research suggests this may be a side effect of its primary job as a stress-buster.

Researchers manipulated ghrelin levels in mice through a variety of methods, including prolonged calorie restriction, ghrelin injection and a genetic modification rendering the mice numb to ghrelin’s effect.

Mice who had limited ghrelin activity seemed depressed. If pushed into deep water they made no effort to swim. When introduced to a maze, they clung to the entryway. And when placed with other mice, they tended to keep to themselves. (These behaviors were reversed when the mice were given a low-dose antidepressant commonly prescribed to humans.)

In contrast, mice with high levels of ghrelin swam energetically in deep water, looking for escape. They eagerly explored new environments. And they were much more social.