YOU ARE WHAT YOUR GRANDPARENTS ATE

Diet — or lack of it

In the winter of 1944, as World War II was nearing its end, the Germans imposed a food embargo on a densely populated area of western Holland. At that time, the weather was unusually severe, agricultural land had been ruined by the war, and the people were already short of food. Some 30,000 people died. Pregnant Dutch women who starved during that famine but survived had smaller babies. That, of course, came as no surprise. But what was a surprise was that, when those babies grew up, even though the war was over when they were infants and they had been well fed and no genes had been tinkered with, they went on to have small babies themselves.

Detailed birth records collected during the 'Dutch Hunger Winter' allowed scientists to analyse the long-term health effects of prenatal exposure to famine. Not only have researchers linked such exposure to a range of developmental and adult disorders, including low birth weight, diabetes, obesity, coronary heart disease, breast and other cancers in that generation, at least one group has also associated exposure with the birth of smaller-than-normal grandchildren.[1]

This finding is remarkable because it suggests that a pregnant mother's diet can affect her health in such a way that, not only her children but her grandchildren and possibly generations even further down the line could also inherit the same health problems.

Another piece of evidence came when a fascinating article by Marcus Pembrey, Professor of Clinical Genetics at the Institute of Child Health in London, and co-workers was published in 2005.[2] This suggested that the behaviour — or environment — of boys before puberty could influence the physical characteristics of their sons and grandsons. Pembrey's team used data collected in the Avon Longitudinal Study of Parents and Children (ALSPAC), which showed that early paternal smoking was associated with greater body mass index (BMI) at 9 years of age in sons, but not in daughters. This prompted them to re-examine the records of the 1890, 1905 and 1920 cohorts from Överkalix, an isolated community in Northern Sweden, from which they had previously reported an association of ancestral food supply with life-expectancy[3] and with cardiovascular and diabetic mortality.[4]

Överkalix is unusual in that the town's birth and death records are remarkably detailed. The records give not only the dates you would expect, but causes of death as well. And the records don't stop there: they also give accounts of the living conditions in such detail that availability of food in the area can be defined by referring to historical data on harvests and food prices, records of local community meetings and general historical facts over centuries.

Dr Pembrey collaborated with Swedish researcher, Dr Lars Olov Bygren of Umea University. Their research showed that a famine at critical times in people's lives, and their slow growth period just before puberty, could affect the life expectancy of those peoples' grandchildren.[5] Data were collected by following up children born in 1905. The individuals studied were characterised by their parents' or grandparents' access to food during their own slow growth period. What the data demonstrated was that, if there was plenty of food in the environment when the paternal grandfather was a 9- to 12-year old boy, that shortened the life of the individual offspring studied, even though that individual was well-fed himself. In other words, you are what your grandparents ate.

It was the first evidence that an environmental effect could be inherited in humans.

The affects of different carbohydrates

It is now known that eating a meal stimulates the release of numerous hormones that can powerfully affect gene function. A study conducted at the University of Kuopio, Finland, assessed the effect of carbohydrate modification on gene expression with the features of the metabolic syndrome.[6] Eating wheat, oats or potato up-regulated 62 genes related to stress, cytokine-chemokine—mediated immunity, and the interleukin pathway, changes that are not desirable, whereas rye pasta down-regulated 71 genes and up-regulated none.

Molecular pathways involved in hormone action have been the target of a multibillion-dollar pharmaceutical research effort. However, many of these pathways may normally be under dietary regulation. The results of this Finnish study illustrate the sense inherent in the age-old wisdom to 'use food as medicine'.