TMAO: an unjustly accused compound or nutritional toxin? By Jerry Brainum

 

 

For years, various scientists and alleged nutritional experts warned that eating red meat would eventually produce cardiovascular disease. They said this despite the fact that there was little or no direct evidence to prove such an assertion. When pressed for the reasons as to how red meat could produce cardiovascular disease (CVD), the usual explanation was "because it's rich in saturated fat." Saturated fat was thought for years to be a direct precursor for cholesterol production in the liver, and elevated blood cholesterol was linked to CVD onset. But as time went on, the picture related to what actually causes CVD became clearer. For example, it wasn't total cholesterol that was the problem with CVD. Instead, the true culprit turned out to be a cholesterol-protein carrier in the blood called low-density lipoprotein (LDL). But even LDL turned out to be relatively innocent. LDL was only dangerous and linked to CVD onset when it was oxidized. LDL was the primary transporter of cholesterol in the blood and performed some vital functions. For one, it delivered cholesterol to the Leydig cells of the testes, where the cholesterol served as the raw material for the production of both testosterone and estrogen. Cholesterol was also the precursor for vitamin D production in the skin, as well as various other steroid hormones in the body. Not to mention that cholesterol also played an important role in stabilizing cellular membranes. Without cholesterol in these membranes, the cell would collapse. In relation to meat, there was no evidence ever produced showing that eating meat tended to promote the oxidation of LDL, thus turning a beneficial compound into a dangerous substance.

But what about saturated fat? We've been told for years that consuming large amounts of saturated fat would inevitably lead to CVD. Yet, more recent studies that have looked at the relationship between saturated fat and CVD found none. While a high intake of saturated fat does indeed boost cholesterol production in the liver, that increased production of cholesterol alone doesn't seem to be responsible for CVD onset. Based on older epidemiological studies that were suspect to begin with, the U.S government and various nutritional authorities advised people to limit their intake of saturated fat to no more than 10% of daily caloric intake. This advice would not be good for anyone engaged in resistance exercise for purposes of adding muscle mass. Saturated fat is one of two types of fat (the other being monounsaturated fat, as found in olive oil and other sources) that are required for the production of testosterone in the body. Studies show that men need to ingest at least 20 percent dietary fat intake each day to maintain normal testosterone synthesis. Although the precise reason for this fat requirement isn't clear, it may partially relate to the connection between saturated fat and cholesterol production, since as noted, cholesterol is the raw material needed to produce . . .