What are nutritional guidelines?

Nowadays, information on healthy eating can be found everywhere, from social media to the weekly glossy cover of your local supermarket’ magazine.

As such, consumers are constantly being confronted with nutritional information. However, how do you know whether the information is reliable?

To help you make the healthy choice and to improve public health, many countries have developed nutritional guidelines. In this article, you will learn what nutritional guidelines are and how they are designed.

What are nutritional guidelines?

In brief, nutritional guidelines are a practical tool to promote healthy behaviour. Here are some common features:

• Developed by governmental institutions.
• Based on scientific evidence.
• Country-specific, which means they cannot be one-on-one applied to the situation of another population.
• Aim to prevent chronic lifestyle diseases (such as type 2 diabetes and cardiovascular disease).
• Serve as the basis for nutrition education for the public.
• Provide dietary advice for the general population and to people of all age groups and life stages.

Since the guidelines are used as a tool to promote healthy behaviour for the general population, they are not always adequate on an individual level. Although dietary advice may also benefit certain groups of patients, they are not disease-specific. Some patients’ groups need specific dietary recommendations, which are not always addressed in the nutritional guidelines.

The development of nutritional guidelines

Let’s take a closer look at how the nutritional guidelines are being designed. As an example, we use the Dutch Dietary Guidelines, which were published in 2015. These guidelines describe the nutrients, foods and dietary patterns needed to achieve health gain. The evidence is based on the international scientific literature. In the first step, a scientific committee of the National Health Council evaluates three types of studies:

1. Cohort studies: studies in which the exposure (e.g. dietary intake) is measured before the outcome is determined (e.g. diagnosis of disease). These long-term studies make it possible to study the development of chronic disease. For example, the Nurses’ Health Study, showed that obesity correlated with a higher risk of developing type 2 diabetes, cardiovascular disease, and breast cancer.
2. Experimental research: studies that examine what happens when the researcher changes the exposure level. These types of studies provide information about the “causality” between the exposure and the outcome. As these studies are often shorter than cohort studies, they mainly study risk factors of chronic diseases, such as high blood pressure or overweight. For example, the PREDIMED study in which the effect of three different diets on having a heart attack was studied. The three diets were: 1) Mediterranean diet supplemented with olive oil; 2) Mediterranean diet supplemented with nuts, and 3) A control diet encouraging low-fat food items.
3. Meta-analyses: studies in which the results of cohort studies and experimental research are combined. This type of study provides the highest level of evidence.

After all the literature is evaluated and reviewed, the committee summarizes all the evidence. They determine the level of intake of dietary factors that have positive and negative effects on health.

These conclusions are then formulated as dietary recommendations about the intake of nutrients, foods, and dietary patterns.

The Dutch Dietary Guidelines

In practice, the recommendations of the Dutch Dietary Guidelines look like this:

• Follow a dietary pattern that involves eating more plant-based and less animal-based food, as recommended in the guidelines.
• Eat at least 200 grams of vegetables and at least 200 grams of fruit daily.
• Replace refined cereal products with whole-grain products.
• Limit the consumption of red meat, particularly processed meat.
• Minimize consumption of sugar-containing beverages.
• And many more…

Practical translation of the dietary recommendations

In the next step, the dietary recommendations are translated into public information material by the Netherlands Nutrition Centre. This practical information tool is called the ‘Wheel of Five’ and consists of five segments that contribute to health benefits.

It describes everyday dietary choices for men and women, various age groups and cultural backgrounds. It includes sufficient variety and provides adequate amounts of vitamins and minerals.

The Wheel of Five

With the Wheel of Five, consumers are encouraged to improve their own diet by making healthy dietary choices. The Wheel of Five also takes sustainability into account, by promoting a more plant-based dietary pattern.

The Wheel of Five is a circular information model that represents the optimal servings of food groups to be eaten every day.

Figure 1. The Dutch “Wheel of Five”

Note that all images from this article can also be found in the Downloads section, where you can zoom in for better visibility.

Other examples of a circular model are the Eatwell Guide (United Kingdom), the Nutrition Cycle (Germany), and the Food Circle (Iceland).

The food pyramid

Another popular model is the food pyramid. This infographic has a broad base for food groups that are recommended in high quantities – like fruit and vegetables – and narrows upwards to food groups that should be limited – like food and drink high in sugar.

The Food Pyramid model is used in for example Ireland, Estonia, Spain, and Croatia.

Figure 2. The Irish “Food Pyramid”.

Authors: Dr. Tim van Zutphen and Dr. Edith Visser