The impact of alcohol on folate levels was neatly demonstrated 1973 by Edward Eichner and Robert Hillman , in some experiments that some of us might wish we could have volunteered for. People were given alcohol to drink – or by intravenous injection – and the researchers measured the levels of folate in their blood.

According to the original research paper, “subjects who were placed on oral alcohol ingested one ounce of pharmaceutical grade alcohol every 2 hours while awake, for a daily equivalent to a pint of commercial whiskey”. It’s unclear from the paper whether this came with ice and slice, but I suspect not… Anyway, the researchers found that folate levels in the bloodstream fell following drinking over several hours, although brief bouts of boozing didn’t cause such a drop (phew!).

So what’s the big deal here? How does a blip in folate levels affect our health? Well, for a start we know that excessive alcohol intake can increase the risk of a number of types of cancer, including bowel and breast cancer. It’s likely that faulty DNA methylation (due to a lack of folate or methyl-THF) plays a part. Researchers have shown that cancer cells generally have lower levels of methylation across all their DNA, suggesting that many unwanted genes might be switched on, stimulating the cells to multiply.

However, cancer cells also have an increased number of methylation ‘hotspots’ at certain crucial cancer-protection genes, switching them off and preventing them from working. Both of these effects have been blamed on low folate levels, generally messing with the normal methylation patterns in the cell. But what’s the evidence?