A Recipe for Longevity Food affecting human lifespan
W
estern society demands quick fixes. We want to open the newspaper and read about the latest silver bullet to cure ageing and obesity. Unfortunately, it is rarely that straightforward. Humans are complex creatures and no single approach is going to provide us with the answer for health and longevity.
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What is the best diet to keep us living longer?”
The gods had it sussed: their food and drink served not only to satiate, but also to immortalise. Ancient mythology is rich with stories of elixirs of youth and golden apples and tales like these are associated with the notion of immortality today. But the idea that diet is critical for longevity is not as fanciful as mythology would lead us to believe. Eating takes up 38,000 hours of our lives and therefore maybe it’s
unsurprising that food can profoundly affect our life and how long it lasts. The general advice for dining table choices may be worth listening to: stay away from sugar, avoid processed food and eat fewer carbohydrate-rich meals. But advice that focuses on the apparent life-extending properties of individual chemicals in food can seem a little farfetched. Take one look at the number of interactions in a metabolic map and you’ll realise how futile this approach is. While talking about specific chemicals is pointless, pulling out the balanced diet card could seem a little vague. Striking the balance between protein, fat and carbohydrate is critical, but it could be an easy way to skirt around the incredibly complex problem; what is the best diet to keep us living longer? We have a very good answer for mice. Because scientists can raise them from birth and measure any effect of diet on health and lifespan, the most effective longevity diet for mice has been identified. A low-protein, high-carbohydrate diet is associated with the longest lifespan, whilst the effects of calorie restriction are at best equivocal. But it seems that we haven’t yet reached this level of knowledge when it comes to human diets. It’s inconceivable to think we could perform such a detailed and controlled study on humans, and, even if we could, the results m i g h t not look like those found in mice. But
from what is known so far, a high-carbohydrate diet is certainly not the answer for humans. Human trials have to rely on abnormal states, such as Elevated levels of bad cholesterol; the resulting symptoms can then be altered by experimental dietary changes. Thus, as a result of the research possible, human dietary recommendations are usually limited to those that reduce a person’s disease risk rather than alter the lifespan itself. Such studies show that to reduce your chance of obesity, eating food that has minimal effects on blood sugar levels is the best bet. These low sugar foods avoid triggering the insulin response that tells your cells to store fat. For heart disease, reduction of salt and fat intake and an increase in the intake of fruit, vegetables and fibre can improve blood pressure and lower levels of bad cholesterol. Currently, the best advice we have pertaining to human diet is “Diet X will reduce your risk of Y” – this is as much as current evidence supports. Reading too much into the results of epidemiological studies has produced decades of confused dietary recommendations, which often assume that one diet suits everyone. Unfortunately, experiments that give instructive results about the best diets are impossible to conduct on humans. In lieu of this, for longevity through diet I would follow the advice of the author Michael Pollan: “Eat food. Not too much. Mostly plants.”
Reported by Raphealla Hull Art by Michael Mackley
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