The One Thing Every Good Diet Has in Common: Nutrient Density

There is no one size fits all approach to nourishing your body for optimal wellbeing, and the Blue Zones are an example of just that. The Blue Zones are specific areas around the globe that are home to the healthiest, longest-living populations on the planet. Many scientists and researchers attribute the long lives of people in the Blue Zones, in large part, to their healthy diets and lifestyles. And while the specific types of foods consumed vary dramatically from one Blue Zone to the next, there is one very important dietary concept they all share in common: nutrient-density.

What is Nutrient Density?

Simply put, Nutrient density is a measure of how full a particular food is of nutrients. The more nutrient-dense a food is, the healthier it tends to be for our bodies. You can think of nutrient density as a way to maximize the nutritional bang per bite of a food.

In general, minimally processed, whole foods tend to be the most nutrient dense foods. Blue Zone diets tend to be filled with these. Alternatively, the more processing a food undergoes, the less nutrient dense it typically becomes. This is because processing tends to 1) strip away or destroy some of the most nutritionally beneficial parts of a food, and 2) processing usually involves the addition of salt, refined oils, or sweeteners, which tend to be energy-rich and devoid of health-promoting nutrients. Countries outside of the Blue Zones tend to eat diets filled with highly processed foods.

To understand these differences better, let’s look at brown rice. The reason brown rice earns the title “whole grain” is because it retains all 3 parts of the grain: the bran, the germ, and the endosperm. However as brown rice is further refined, the bran and the germ are stripped away, and the fiber and nutrients found in these portions of the grain are lost as a consequence. The outcome of this processing is what we know to be white rice, which now has a much lower nutrient density compared to its original brown rice version, because the white rice has lost a host of nutrients during processing.

A food’s nutrient density can also decrease during processing due to the addition of oil, sugar, and salt. For example, a strawberry picked right off the bush is in its most nutrient dense state, filled with vitamins, minerals, fiber and other healthy compounds like phytonutrients. Conversely, if we take that same strawberry, and we process it into strawberry jam, the nutrient density drastically declines. That's because during processing, sugar is typically added, which increases the calorie content, and therefore dilutes the nutrient density of the food.

Quantifying Nutrient Density

Everyone in the scientific community would agree that to maximize the nutrient density of a food, a good rule of thumb is to choose minimally processed foods in their most naturally-occurring, whole-food form.

In theory, this is great advice. But in practice, it’s wildly unhelpful. In the real world, processed foods exist, at varying degrees and they will continue to persist. And to some extent, the processing is necessary for feeding a global population. Processing can help preserve foods, extending shelf life and protecting us from food borne illness. Processing can also increase the convenience of a food (think canned beans). And, depending on the nutrient, sometimes processing can enhance the bioavailability of a nutrient, such as with lycopene in canned tomatoes. In that case, the processing actually makes the lycopene in tomatoes more absorbable to our bodies. The reality is, not all processing is “bad”, and some level of processing will always exist. With that in mind, simply “eating whole foods” is not the most helpful advice for consumers. It’s easy to conclude that an apple is more nutrient dense than apple juice. But what about comparing one processed food to the next. For example, which yogurt is more nutrient dense? Which nutrition bar is more nutrient dense? What consumers need is a tool to help them discern between which choice is the most nutrient-rich choice.

This is where many believe nutrient density can play a role in helping consumers make choices with their foods. Calories and macronutrients like carbs, proteins and fats have become common for consumers to consider when thinking about their diets and food choices. Can nutrient density be similarly simplified to a single number used for food comparison? The answer, as is often the case in nutrition, is not so simple.

In our next blog post we will look at the complexities of nutrient density and consider how to begin presenting a simple, usable scoring system to help consumers apply nutrient density in making food choices that are right for their individual needs. Please let us know your thoughts in the comments below.