Diet or genes?

What drives degenerative conditions?

In the days of Hippocrates, diseases were blamed on the gods. Nowadays a lot of degenerative conditions are being blamed on genes – because knowledge about genes and their effects has advanced tremendously over the last several decades. Genes are the code, or instructions, to assemble proteins, for example to make an enzyme, a hormone or a biochemical such as cholesterol or phospholipids.

Are genes fixed and unchangeable?

A gene variant is like a dimmer switch and can be ‘over-expressed’ or ‘down-regulated’ – turned up or dimmed down. That is why approximately half of women with the BRCA gene develop breast cancer and half do not. The environment the gene is exposed to makes all the difference.  ‘Adherence to healthy dietary patterns (vegan) was significantly associated with the down-regulation of pro-metastatic (cancer) genes.’ concludes a recent study in the European Journal of Nutrition on women with the BRCA gene. 

In addition the expression and harmful effects of the ApoE4 ‘Alzheimer’s gene’ appear to be down-regulated by restricting processed carbohydrates in a Mediterranean style diet including fatty fish, cruciferous vegetables, olive oil, and low alcohol consumption. Six supplemental nutrients with evidence of down-regulating ApoE4 are omega-3 DHA (in salmon, mackerel and herring), B-vitamins (B2, B6, B12 and folate), vitamins D3 and K2, quercetin and resveratrol.

A recent 10 year study in China assessed the diet and lifestyle of 29,072 people of whom 20% had the ApoE4 gene to see who would or would not develop cognitive decline or dementia. The study showed that whether or not a person had the ApoE4 ‘Alzheimer’s gene’ made no difference to the positive reduction in risk achievable by simple diet and lifestyle changes.  Those with a healthy vs unhealthy diet were nine times less likely to develop dementia.

And how much risk does an unhealthy lifestyle add?

The predictive risk for Alzheimer’s of having a low intake of seafood and/or omega-3 fats is 22%. It is similar for smoking, and also for a low intake of B vitamins – which results in a high blood level of the toxic amino acid homocysteine associated with narrowing and hardening of the arteries and a 17-fold increased risk of cerebrovascular dysfunction.  

Low B vitamin intake (B6, B12 and folate) also disrupts the methylation (detoxifaction) gene MTHFR677TT increasing homocysteine and the risk of Alzheimer’s and contributing to many other degenerative conditions including schizophrenia and cancer.   

In a placebo controlled study of older people with mild cognitive impairment, about a third of participants had the MTHFR variant that increases Alzheimer’s risk. But supplementing with B vitamins effectively lowered homocysteine in both those with and without this ‘Alzheimer’s’ gene. It also arrested further memory decline and slowed the rate of brain shrinkage by 52%, reducing shrinkage of the Alzheimer’s areas of the brain by 9-fold. The same has been shown in other studies giving Omega-3 to reduce cognitive decline, especially in combination with B vitamins.

So you can change your diet and lifestyle and significantly reduce your risk of degenerative conditions.

Too often genes are blamed as drivers of degenerative conditions even though the primary drivers are what you put in your mouth or how you live your life – both factors under our control. For example, DNA genetic testing can cause panic when an individual is informed they have gene variants that increase their risk. Over-emphasising the importance of genes discourages people from preventing degenerative conditions by improving diet and lifestyle.

Extracted from two fully referenced articles by Patrick Holford at