Yogis are by far the healthiest eaters I have ever met. If you’re reading this blog, you’re probably one of them – faithful in the observance of your Yamas and Niyamas – leaving me reluctant to confess my own (pre-yoga) pizza-scarfing, soda-swilling ways. Please don’t hold it against me. I’ve changed, really.
Here – as plain as I can make it – is the scientific reason why eating a low-calorie vegetarian diet is a good thing. Good, as in living longer and cancer-free.
All you need to know is that when you eat less, your levels of Nicotinamide adenine dinucleotide (NAD – the contorted, yogic-looking molecule shown at left) are HIGH – and this increases the activity of the “longevity gene” SIR2. The amazing life-extending effects of the NAD-dependent SIR2 genes are described in detail on Leonard Guarente’s website at M.I.T.:
The discovery that Sir2p requires NAD for its activity immediately suggested a link between SIR2 activity and caloric restriction. This link was strengthened by the observation that life span extension by caloric restriction requires Sir2 protein. Caloric restriction is likely to reduce the carbon flow through glycolysis and result in more free cytoplasmic NAD. SIR2 could act as a sensor of NAD levels within the nucleus. Under conditions of caloric restriction, NAD levels are high, SIR2 is activated, and the rate of aging is decreased.
The hard science link between cancer and NAD is more recent – this week in fact - with the release of a study entitled, “Transcriptional regulation of BRCA1 expression by a metabolic switch” [doi:10.1038/nsmb.1941]. Here the researchers found that NAD/NADH levels via binding to CTBP1 can regulate the anti-tumor properties of BRCA1. In a nutshell, a high-calorie diet leads to LOW levels of NAD which has the net effect (via CTBP1) of turning OFF the anti-tumor gene BRCA1 (a bad thing). From the article:
The elevated expression of estrogen in the context of higher levels of NADH or lower NAD+/NADH ratios due to high caloric intake and/or obesity could establish a state in which the pro-proliferative effects of estrogen are not completely balanced by the protective functions of BRCA1 that would normally restrain estrogen-induced proliferation and heighten genome surveillance.
I realize that most yoga folks need no such hard science to convince them of the merits of a low-calorie, healthy diet. In the science-world however, empirical evidence can take decades to gather, so its an important milestone to now have established causal links between caloric intake, longevity and cancer risk.
For (former) junk food junkies like myself, there is no room to debate or side-step the issue. Eat less, eat healthy – live longer and cancer-free. More on yoga and aging (here, here, here). Now, off to the shala for NADasana pose!