U.S. Marines unload ready-to-eat rations in Léogane, Haiti. Despite aid efforts, malnutrition continues to contribute to 60% of deaths among children under the age of five in developing countries, and some scientists think the nascent science of nutrigenomics holds the answer.
Credit: U.S. Department of Defence
Starving people do not just need food. They need the right nutrients to maintain and promote good health. Food aid can help prevent starvation, but if it is not nutritionally balanced it could also contribute to chronic diseases and premature death.
Supplying key nutrients — through either whole foods, fortified foods or supplements — is especially important in developing countries, where malnutrition contributes to about 60% of deaths among children under the age of five each year, according to Médecins Sans Frontières.
But what levels of nutrients are needed to maintain good health and prevent disease? To answer this crucial question, we must turn to nutrigenomics — the study of the interplay between food and genetic make-up.
Stark differences in populations genetics
A person's genes determine how their body absorbs and uses nutrients. Because each person is genetically unique, the amounts and types of nutrients needed to maintain good health might differ among individuals.
They can also differ between historically separated populations that have genetically adapted to cope with different local environments.
The most visible difference caused by this adaptation is skin colour. The variation from pink to brown not only helps to prevent sunburn but also allows appropriate amounts of sunlight to penetrate the skin to create the vitamin D3 from its inactive precursors.
A less obvious genetic adaptation is lactose persistence, which describes the continued production into adulthood of the enzyme lactase that metabolises lactose, the sugar found in milk. Most mammals stop producing lactase after weaning but those humans who could drink milk had access to protein, calcium and water, helping them survive the harsh climates of northern Europe and central Africa.
As a consequence, more of their descendents survived and bore the variant lactase gene. Many northern Europeans and central Africans retain the ability to drink milk, whereas about 70% of the world's population are lactose intolerant.
Differences in metabolism from environment
Differences in population genetics can also result from historical deficiencies or excesses of nutrients in soils, plants and animals. For example, the lack of iron, selenium or other micronutrients in the diet may have selected for genes that aid the uptake, storage and use of these essential nutrients.
Similar forces acted on domesticated plants and animals. For example, rice grown in the delta region of Arkansas is chemically and nutritionally different to rice grown in India because the local soils, rainfall, temperature and other conditions affect the plants' growth, maturation and chemical make-up.
The main implication of this genetic variation in the developing world is that food alone is not enough. The wrong kind of food can be just as damaging to people's health as a lack of food.
Consider, for example, the epidemic of obesity and chronic diseases that affects not only food-secure countries but also urban areas of developing countries, such as China, where one in six people (215 million individuals) are overweight, according to the definition set out by the World Health Organisation.
