杏吧原创

Is there a single foodstuff that could provide all the nutrients a human needs to stay reasonably healthy indefinitely?

鈥� Any single substance such as water or fat? No. Any single tissue such as muscle or potato? No. But if we allow free drinking water and air to breathe 鈥� even though those are also nutrients 鈥� then we can relax our rules. Even so, drinking milk while eating corn would count as two foodstuffs, and who knows how many foodstuffs pizza contains.

Not surprisingly, no strict monodiet can rival any healthily balanced diet, but there are two classes of foodstuffs that in appropriate quantities can maintain a reasonable level of health. One such class is baby food. Examples include eggs, milk, certain seeds, and so on. None is a perfect option, but some are adequate.

Alternatively one might cheat by counting essentially whole animals: oysters or fish such as whitebait or sardines might supply the necessary nutrient uptake. Animals sufficiently closely related to humans might also do, if eaten in the correct form and quantity. Farming families in the semi-desert Karoo region of South Africa apparently ate mainly sheep or cattle.

For the most perfectly balanced human monodiet, however, other humans would be the logical food of choice. Not sure there would be many takers though.

鈥淔or the most perfectly balanced human monodiet, other humans would be the logical food of choice鈥�

Jon Richfield, Somerset West, South Africa

鈥� Despite various claims made over the years for spinach, baked beans or bananas, the answer is 鈥渘o鈥�. To remain healthy over the course of a natural lifetime, a human needs a balanced diet, with a combination of carbohydrates and protein and a proper range of vitamins. The balance may vary with age, from individual to individual, and even between societies in differing environments, but balance is the key to healthy eating.

Probably the most homogenous diet of any human community is that of the Inuit in Arctic North America, which traditionally consists of 90 per cent meat and fish and effectively no carbohydrates. The explorer not only established that Inuit hunters often lived for between six and nine months of the year on a wholly carnivorous diet, but also claimed to have sustained himself by eating just meat and fish on his expeditions.

In a series of controlled experiments under the auspices of The Journal of the American Medical Association, Stefansson and a number of his colleagues reproduced the dietary regime they had followed in the Arctic, without any apparent ill effects and without, much to the supervising doctors鈥� surprise, developing scurvy. However, subsequent long-term studies of health factors in the Inuit community have established a strong correlation between the carnivorous diet and early deaths among Inuit men from heart attacks and other cardiac problems.

The bottom line is to remember what your mother told you: always eat your greens.

Hadrian Jeffs, Norwich, UK

鈥� Humans have been suggested as the ideal diet for other humans, but eating human flesh would not satisfy all our dietary needs, no matter how healthy the diner or victim, for a very simple reason: not every nutrient, mineral and vitamin in the body remains available to the next step in the food chain. Some substances are 鈥渦sed up鈥� and others are built into indigestible tissues and structures.

Cooking can increase the digestibility of many foodstuffs for a human, but things like hair, bones and teeth cannot be prepared to make them amenable to our digestion. However, we need the minerals, amino acids and other nutrients in them to make these substances for ourselves.

The human body is a tenacious machine and will continue to survive on a very poor diet for quite a while. Many people living in harsh climates have their own dietary supplements in local foods and 鈥渄elicacies鈥� that they may not even realise are making up a shortfall. The same is true of those who live in a self-imposed harsh regime, such as true vegetarians. One can live on such diets and remain healthy as long as there is a balanced variety of nutrients, or by taking artificial supplements such as vitamin B₁₂.

Some natural foodstuffs provide a reasonable balance of necessary nutrients, but the only known and proven foodstuffs that truly provide everything that a human body would need, in a single wrapper, are manufactured. Survival rations and trail foods are many and varied, but remain unpopular because they are generally dry and unpalatable.

Foods made to cover all the needs of large and physiologically similar mammals, such as dogs, pigs and other omnivores could probably sustain us very well too, although we may have to eat more of the stuff than we鈥檇 like to get sufficient supplies of any human-specific nutrients.

Nat Guthrie, By email, no address supplied