What does science say about healthy nutrition?

1. Conflicting views on healthy food make it increasingly difficult for consumers to make the right choices. That is why it is important to map the scientific state of affairs with regard to healthy foods and the connection with diseases such as diabetes, cancer, cardiovascular diseases and with all-cause mortality (all-cause mortality). So-called meta-analyzes are used to draw responsible conclusions. It analyzes and summarizes the best studies of such relationships.

Fruit and vegetables

1. The basis of any healthy diet is formed by fruits and vegetables, which offer an enormous variety of nutrients with sufficient variety. A German study from 2012 1 shows how far-reaching the benefits are of a high consumption of fruit and vegetables for the prevention of chronic diseases. The researchers conclude that the evidence is convincing with regard to high blood pressure, strokes and coronary heart disease (the cut-off of the blood supply to the heart muscle). With less certainty, this is concluded for cancer, the lung diseases COPD and asthma, rheumatoid arthritis, eye diseases, osteoporosis (bone loss) and dementia. [! 180374 => 1130 = 370!] Dose response

1. A meta-analysis published in 2017 22 provides an overall picture of the positive influence of fruit and vegetable consumption on health, in particular the protection it offers against cardiovascular disease, cancer and premature death. This research has two important advantages over previous analyzes: it is calculated for which amount of fruit and vegetables the benefits are maximal (the dose-response relationship) and a distinction is made between the effects of different types of these foods. The conclusions are summarized here.

Herbs and Spices

1. Of underestimated importance to health is the use of herbs and spices, which have a long history of medicinal use. Only in these modern times is scientific research on their positive health effects on a larger scale. This research does not yet lend itself to firm conclusions. It does show, however, that herbs and spices represent an astonishingly great health potential 23 and that they show great promise in relation to cardiovascular diseases 24 and cancer, among other things. 25

Fatty fish

1. Immediately after fruit and vegetables (and herbs), the first recommendation is fatty fish, such as herring, tuna, salmon, sardines or mackerel. It provides good protein and is an important source of a range of nutrients, including vitamin D. However, the positive health effects are mainly related to the polyunsaturated fatty acids present in fish. These are eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which are counted among the so-called omega 3 fatty acids. These are present in fish due to their consumption of algae.

Cardiovascular diseases

1. Research shows that fish consumption reduces all-cause mortality. 26 This is mainly due to the protective effect of fish fatty acids on heart and blood vessels. This has been shown in two meta-analyzes 27 from 2004 for coronary heart disease, but also for sudden cardiac death. 28 In addition, fish consumption has a preventive effect on heart failure (heart failure) 29, a serious condition in which the pumping power of the heart is greatly reduced. [! 180374 => 1130 = 374!] Cancer

1. The lower mortality from fish consumption is also due to the protective effect on various cancers. The evidence concerns colon cancer 30, lung cancer 31, breast cancer 32, liver cancer 33, esophageal cancer 34, ovarian cancer 35 and brain tumors. 36 The risk of death from prostate cancer also decreases. 37

Cognition

1. Also important is the protection that omega 3 fatty acids offer against the deterioration of cognitive abilities. Sufficient fish intake in particular reduces the risk of dementia and Alzheimer's disease, as well as Parkinson's disease. 38

Notes

1. Nuts are a supplier of iron and vitamins B1 and E. But, just like fish, they are mainly an important source of fats. These are probably responsible for the beneficial effects on health. Most types of nuts consist of more than half of (largely unsaturated) fat.

Dietary fiber

1. Fibers are carbohydrates from vegetable sources that are not digested in the small intestine. They are called fermentable when they are broken down in the colon and non-fermentable when they leave the body without being broken down first. Fiber has no nutritional value, but it accelerates the passage of absorbed food through the gastrointestinal tract, for a faster feeling of satiety, an increase in the amount of stool and an accelerated elimination of toxins.

Dose response

1. There is a clear dose-response relationship, especially in cardiovascular diseases. For example, a meta-analysis 44 over the period 1990-2013 showed that for both coronary heart disease and cardiovascular disease in general every 7 grams of extra dietary fiber per day resulted in a risk reduction of 9 percent. That 7 grams corresponds, for example, to a portion of whole grains in combination with a portion of beans or lentils or two to four portions of vegetables and fruit. A similar increase in fiber intake by 7 grams daily led to a 7 percent risk reduction for strokes 45, according to another study.

Legumes, whole grains, dairy

1. Vegetables, fruits, herbs, fish and nuts feature in most of the recommended diets and the health benefits are obvious. This is somewhat more complicated for a number of other categories of foods, because some nutritional advice does not recommend these. It is about:

Whole grains

1. A sufficient intake of whole grains reduces the risk of coronary heart disease and other heart diseases 52 and of strokes. 53 Whole grains also have a protective effect on the development of diabetes. 54 It also decreases the risk of pancreatic cancer. 55 In general, the risk of cancer, as well as that of respiratory and infectious diseases, is decreasing. Together these effects probably explain that consumption of whole grains reduces overall mortality. 56

Legumes

1. The risk of cardiovascular disease in general 57 and coronary heart disease in particular 58 decreases with the consumption of legumes.

Dairy

1. In the case of dairy, a risk reduction applies for coronary heart disease 59 and stroke 60, although it is not entirely clear which type of dairy is responsible for this effect and whether that effect varies with the fat content of these Products. All-cause mortality is slowed down by dairy. 61 In addition, dairy products, in particular the low-fat varieties and yogurt, protect against breast cancer. 62

Eggs

1. Eggs contain many healthy nutrients, including eighteen vitamins and minerals. They contain fatty acids that are mainly monounsaturated and also all amino acids that make them a very high-quality source of protein. Consumption of eggs is highly recommended, albeit with some caveats.

Cardiovascular diseases

1. Eggs have long been suspected because of their high cholesterol content. Another Dutch meta-analysis 63 from 2001 concluded that there was an increased risk of coronary heart disease. But that was only possible on the premise that an unfavorable cholesterol profile would determine that increased risk, a link that is currently under discussion. Without going into this discussion, it can be concluded that in most of the 64 subsequent analyzes no direct link was found between egg consumption and an increased risk of cardiovascular disease. The link with coronary heart disease and stroke is absent and consumption of up to one egg per day can even reduce the risk of a stroke 65, according to two meta-analyzes from 2013 and 2016. At the same time, there are signs that (too many) eggs increase the risk of diabetes and an increased risk of cardiovascular disease among diabetics, 66, a correlation which, however, is not found 67 or hardly 68 in other studies.

Cancer

1. The lack of clarity about the advantages and disadvantages of eggs is further increased because meta-analyzes from 2014 and 2015 found indications of a (slightly) increased risk of some cancers. These include ovarian 69, breast and prostate cancer 70, as well as some cancers that can develop in the gastrointestinal tract. 71 The conclusions are surrounded by conditions and certainly cannot be generalized to a clear relationship between egg consumption and cancer risk. The very high nutritional value of eggs clearly seems to outweigh any potential drawbacks.

Meat

1. With some hesitation, meat can also be considered one of the recommended foods. It is an important source of protein and includes B vitamins, selenium, zinc and iron. For health effects, a distinction must be made between "white meat" (chicken, turkey, rabbit) and red meat, which includes all meat from cattle, sheep, goats and pigs. Red meat is then divided into unprocessed and processed meat. The latter type includes bacon, salami, burgers and sausages, for example.

Red and white

1. The difference in health effects between white meat and processed or unprocessed red meat is shown, among other things, by a study published in 2014 72 into the association with cardiovascular disease and overall mortality. Those with the highest consumption of processed red meat, compared with those who ate the least, increased the risk of all-cause mortality by 22 percent and of cardiovascular disease by 18 percent. Unprocessed red meat was more weakly related to cardiovascular disease with a 16 percent risk increase, while no association was found with overall mortality. The researchers concluded that every 50 grams per day increase in processed red meat consumption increased the risk of cardiovascular disease and overall death, while an increase of 100 grams was necessary for an increased risk of death from cardiovascular disease. . No increase in risk was found for white meat.

Conclusion

1. A search through the medical scientific literature shows that choosing the right foods has a profound effect on health. The risk of diseases such as cardiovascular disease, diabetes and cancer is drastically reduced and overall mortality is also clearly falling. Healthy food can thus be used in daily life as a preventive medicine against modern lifestyle diseases.