Public health's blindspot

While life expectancy is increasing marginally, countries everywhere are doing badly in their efforts to reduce cancer, heart disease and many of the commonest, chronic illnesses.

Public health, the government sponsored variety, loves to broadcast standardized health messages. It also loves standard, population-wide interventions like vaccination and iodine added to table salt.

What public health does poorly is to understand the huge differences in makeup between you, me and the next person.

Dubbed biochemical individuality, the large variations across the population occur in far more than height, weight and eye color. They include our internal anatomy, functioning of organs and glands, and blood chemistry.

The shape and size of our stomachs can vary to an extraordinary extent, even across healthy people. The way that blood vessels branch and connect can be very different between individuals.

Levels of enzymes and hormones in our bodies range greatly; some people can be quite healthy with levels way outside those labeled as normal in the blood test results your doctor sees.

There is large variation in our requirement for nutrients. This was discovered many decades ago with vitamin C-some people needing very little and others requiring thousands of milligrams daily for good health. Likewise for other nutrients.

When health officials provide mass advice to the public they revert to speaking to a mythical, average person. This is fine when discouraging smoking, a universally harmful practice. There are dangers though when it comes to other health behaviors.

Public health pamphlets and posters across some decades have advised people on how to eat. They mostly tell us to eat less fat and less calories.

The advice on fat may be good for certain people, but what of the person who already eats very low fat due to their taste, fussiness or other reasons? If they heed the broadcast advice and reduce further, they risk nutritional deficiency. Some fats and oils are important for health.

We know that many young women, already underweight, respond to the advice on calories by starving themselves further.

Problems arise because the written advice, or spoken advice in TV campaigns, cannot select who will listen. It cannot be tailored to each listener; if it can be taken the wrong way it will be.