Current dietary recommendations include to eat more fruit. Cherries are a good source of antioxidants that may protect from disease.
Current dietary recommendations are ever evolving. As more studies investigate various aspects of diet and nutrition, the way that we view food changes. Only a few decades ago high carbohydrate, low cholesterol, low fat diets were recommended for health. This advice was visualised as a food pyramid that emphasised carbohydrate, fruits and vegetable at the base, protein and dairy in the middle, and fats, oils and sugars at the top (here). However, the food pyramid was based on no real science and was simply a reflection of the various lobbying powers of the food producers to exert their power and to promote higher intakes of their own food groups. It is now known that adhering to the food pyramid does not benefits health and that the various aspect of nutritional importance that were placed of certain food groups was biased. Further, more detail research into various aspects of nutrition such as fats and vitamins has lead to serious questions regarding previous advice for nutritional intakes.
In contrast to the food pyramid which emphasises carbohydrate, current dietary recommendations are to limit carbohydrates. This is based on the known detrimental metabolic effects of refined carbohydrates which make up a large percentage of the energy in the Western diet. Individuals who are very active can tolerate larger intakes of carbohydrate because the glucose can be used to resynthesis glycogen rather than causing liver overload syndrome and the accumulation of fat in tissues. Also, Europeans may have better insulin sensitivity compared to Asian individuals which may suggest that recommendations for carbohydrate be tailored to genetic make-up rather than adoption of a blanket one size fits all approach. The traditional recommendation to eat complex carbohydrate is not helpful as some complex carbohydrates are digested at faster rates than others. Potato for example is particularly quickly digested and absorbed. Instead whole grain foods should be emphasised along with consumption of legumes.
Although traditionally the recommendation was to limit fat intake, more recent research has highlighted the importance of particular fats to human health. In particular the essential fatty acids have been shown to confer important health benefits regarding cardiovascular disease. However, the consumption of the omega 6 fatty acids is generally too high and the consumption of the omega 3 fatty acids is generally too low. The recommendation to eat more fatty fish is an attempt to redress this imbalance by supplying higher amounts of the less frequently consumed omega 3 fatty acids. The role of cholesterol in cardiovascular disease has also been massively overstated and more recent attention has focussed on the detrimental effects of trans fatty acids. Current recommendations are to limit hydrogenated and trans fatty acids as no safe levels of intake are known. In fact, because trans fats were previously analysed along with saturated fat, this may explain many of the studies finding associations between saturated fat and cardiovascular disease.
Recommendations to limit red meat are based largely on the confounding effects of processed meat. Processed meat is increasingly being linked to detrimental health outcomes, particularly cancer. Because processed meats are also often red meats, this can bias the results of epidemiological studies investigating the effects of red meat on health. Protein from fish is beneficial largely because of the omega 3 fatty acids that it contains. However, recommendations to limit fish intake because of concerns about pollution of larger predator fatty fish has raised questions about the benefits of incorporating fish within the diet. Because the oils are beneficial but the flesh may be contaminated, fish oil capsules treated to remove the pollutants may be the prefered option. High protein diets are now recommended for weight loss as consistently they are found to be beneficial at suppressing appetite and increasing nitrogen retention. Likewise protein from dairy is beneficial because dairy is associated with lower body weights.
The mainstream recommendation to eat more fruits and vegetables is based on evidence that the chemicals contained within plant material may confer health benefits. In particular certain plant material may protect from cancer and cardiovascular disease if consumed regularly. Higher intakes of fruits and vegetables are consistently associated with reduced cancer rates in epidemiological studies. However, the presence of confounding variables should be considered. For example those with healthy lifestyles are more likely to eat fruits and vegetables. Having said that plant food consumption, particularly legumes is has been shown in clinical trials to benefit health. More beneficial however may be fermented plant products resulting in alcoholic drinks. Red wine is consistently shown to benefit cardiovascular health, with both the alcohol and the polyphenol content being shown to play a role. Similarly the caffeine and polyphenols in green tea also show beneficial effects to the health.
The realisation that in northern latitudes the sun is not sufficient to provide adequate year round vitamin D status has been one of the biggest shifts in nutritional science. Previous adult vitamin D recommendations were based on the amount of cod liver oil required to prevent rickets in children. An explosion is research surrounding vitamin D has resulted in a seismic shift in the recommended intake of vitamin D, which may now be as high as 2000 iu per day for those not exposed to strong sunlight. The association between vitamin D insufficiency and cancer, diabetes and weight gain, suggests that the hormonal role of vitamin D has been underestimated considerably. The recommendation to increase selenium intake, based on studies showing selenium deficiencies may be associated with increased cancer rates, has also come about within the last decade. The consistent low selenium and vitamin D levels in Western population suggest they are at considerably higher risk of developing cancer if they do not adopt these recommendations.
