What exactly are you eating? The nutritional 'dark matter' in your food

Mapping the hidden chemical universe in what we eat could lead to breakthroughs in fighting disease, writes David Benton

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WHEN scientists cracked the human genome in 2003 - sequencing the entire genetic code of a human being - many expected it would unlock the secrets of disease.

But genetics explained only about 10% of the risk. The other 90% lies in the environment - and diet plays a huge part.

Worldwide, poor diet is linked to around one in five deaths among adults aged 25 years or older. In Europe, it accounts for nearly half of all cardiovascular deaths.

But despite decades of advice about cutting fat, salt or sugar, obesity and diet-related illness have continued to rise. Clearly, something is missing from the way we think about food.

For years, nutrition has often been framed in fairly simple terms: food as fuel and nutrients as the body’s building blocks. Proteins, carbohydrates, fats and vitamins - about 150 known chemicals in total - have dominated the picture. But scientists now estimate our diet actually delivers more than 26,000 compounds, with most of them still uncharted.

Here is where astronomy provides a useful comparison. Astronomers know that dark matter makes up about 27% of the universe. It doesn’t emit or reflect light, and so it cannot be seen directly but its gravitational effects reveal that it must exist.

Nutrition science faces something similar. The vast majority of chemicals in food are invisible to us in terms of research. We consume them every day, but we have little idea what they do.