Our body is built in a specific mixture of water, proteins, fats, carbohydrates, and other components. We need food to supply enough of these nutrients to sustain growth, repair and maintenance of our
body.
However, when we go grocery shopping, we do not think about these nutrients. What we buy and
what we eat are foods, such as apples, or steak, or pizza.
There is another reason why we should not to think of food or diet only as nutrients. A fundamental
feature of food is that its constituents are coordinated. Foods form a physically intact entity, and
there are biological reasons behind that. To give you an example, nuts are a food with high quantities
of unsaturated fats. They have also high amounts of compounds with antioxidant properties, because
antioxidants protect against the instability of these fats.
Foods are often grouped into groups that are a collection of foods that share similar nutritional
properties or biological classifications. Think of fruits, vegetables, dairy products, or meat. Many
foods are processed before they enter the store. This processing can take place in the food industry.
It is also done by ourselves before we consume foods. Processing of food can serve several purposes.
Adding salt or antioxidants can increase the shelf-life of a food. Processing can also reduce the risk of
food-borne diseases. Examples of this are cooking or freezing. Processing helps to maintain the looks
and taste of foods. It sometimes improves the nutrient content of foods, or the availability of the
nutrients.
A well-known example of food processing is pasteurization of milk. This is done to kill disease-
spreading bacteria. Pasteurization, through heating, does not kill all bacteria present in the food. It
aims to reduce the number of viable pathogens so they are unlikely to cause disease.
Another well-known example is fermentation. That is a metabolic process in which we use good
bacteria or yeast. They convert a carbohydrate, such as starch or a sugar, into an alcohol or an acid.
Fermentation for example makes yogurt from milk.
The foods we consume supply our body with the needed nutrients. Deficiencies of specific nutrients
can cause serious health problems. In the past, on long sea travels without access to fresh foods,
many people suffered from scurvy, with gum disease, bleeding from the skin, and ultimately even
death. Later it was found that scurvy was the result of a lack of foods that contain vitamin C.
Clinical trials of dietary supplementation of nutrients in isolation have shown that many do not work
as intended or even have adverse effects. Despite the well-defined potential anticancer effects of
antioxidants, randomized trials have shown that beta-carotene increases the risk of lung and
stomach cancer. Macronutrient policies, such as encouraging low total fat intake, may also block
intake of apparently healthful foods, such as olives, nuts, and salmon. Therefore, when studying the
health effects of nutrients or foods, a focus on individual nutrients is too limited.
People tend to eat their foods in a certain combination, that is called a dietary pattern. Dietary
patterns vary greatly across the world.
There is a typical Western pattern that is consumed often in the high-income Western countries, like
the USA, and The Netherlands. This diet contains primarily refined grains, processed and red meat,
high fat dairy, fried products, alcohol, sweets and sweetened beverages. Such a diet is high in sugars
and in saturated fats. Animal products are an important food group of the Western diet, and
therefore the environmental impact of this dietary pattern is also very high. The current Western
dietary pattern is considered unhealthy. This diet is a risk factor for a number of chronic diseases
including: high blood pressure, diabetes, overweight and obesity, cardiovascular diseases, and
cancer. Our group recently studied the effect of the Western dietary pattern in the Dutch population.
This pattern is related to a shorter life lived in good health compared to a more prudent diet, that has
more characteristics of the Mediterranean diet.
The Mediterranean diet is the dietary pattern that was consumed in Greece, Southern Italy, and Spain
in the 1940’ and 50’s. It had struck famous investigators as biologist Ancel Keys from the US, that the
incidence of heart disease was surprisingly low in these countries. Therefore they set up the Seven
Countries Study, one of the first formal studies to test the hypothesis that diet is important in heart
disease.
The Mediterranean diet is characterized by high consumption of olive oil, legumes, unrefined cereals,
fruits, and vegetables, fish, moderate consumption of cheese and yogurt, moderate wine
consumption, and low consumption of meat products. It hardly contains refined sugars, and
unsaturated fat instead of saturated fat. Because the focus is more on plant-based than animal-based
foods the environmental impact of the Mediterranean diet is also lower compared to the Western
diet.
The health benefits of the Mediterranean diet have been studied frequently. A Randomized
Controlled Trial into its longer term health effects has even been carried out in Spain. This was called
the Predimed study. This study investigated two variants of the Mediterranean diet versus a control
diet, and found beneficial effects on cardiovascular disease, type 2 diabetes, diabetes complications,
depression, and breast cancer.
Many countries and also the World Heath Organization have now dietary guidelines in place that are
based on the Mediterranean diet. These guidelines show what healthy diets should look like. Our
challenge now will be to combine our knowledge on health and environmental aspects of food
together to find sustainable and healthy diets for our future.
