Nutritional Quality

Comment on the PLOS ONE paper on fatty acids in milk:
“The recent research by Dr. Benbrook and his colleagues provides the strongest evidence to date that milk from cows raised on pasture grasses and legumes on certified organic farms provides more omega-3 fatty acids and improves the overall heart health profile of fatty acids in our diet. Importantly, these results make especially clear that women of childbearing age can directly benefit their babies during pregnancy and lactation by ensuring adequate intake of these essential fatty acids from organic milk”

 

-Dr. Jeffrey Blumberg, Director of the Antioxidants Research Laboratory, Tufts University [source].

 

Overview

How can a person tell if a serving of one food is more nutritious than a serving of a different food?

Your doctor delivers the news that you are on the path to Type 2 diabetes and that you need to make some lifestyle and dietary changes to avoid the disease. How do you identify the components in your daily diet that are contributing to the progression of the disease, as well as foods that you should add to your diet to promote a return to normal blood sugar management?

Many farmers want to produce the most nutritious apple or cucumber or carrot possible, and wonder how they can tell whether they are making progress toward this goal?

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Plant breeders often select for and use genes that both increase nutrient content and intensify the color of fruits and vegetables. Photo from USDA.

Food companies are looking for ways to increase the nutritional quality of their manufactured foods, but how can they sort through the multiple impacts on nutrient content when a single ingredient is changed?

The answer is the same for all four questions – “dial up” a nutrient profiling system. Such systems quantify the nutritional contribution, and hence “quality,” of different foods. By “nutritional contribution,” we mean the portion of a person’s daily nutrient needs that are satisfied by a serving, or a known quantity, of a given food.

There are over two-dozen essential nutrients that people must get via food, or suffer dire consequences. There is another half-dozen to dozen nearly essential ingredients that also have major impacts on health outcomes. Scientists have established “Recommended Daily Allowances” (RDAs), or “Acceptable Daily Intakes,” or “Reference Intakes,” for all or most of these nutrients.

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The USDA maintains measures of recommended daily intakes.

Nutrient profiling systems calculate the percent of a person’s daily need for essential and near-essential vitamins, minerals, and other nutrients that are supplied by a known quantity of a given food.

The score for the food, and all other foods, is the sum of the percentages across all nutrients within the nutrient-profiling system. The higher the score, the more nutritious a given food is.

Nutrient profiling systems strive to take into account most or all of the known, essential and near-essential nutrients in food. Some also include negative attributes in food, such as added sugar and salt or saturated fat content.

The Math Behind Nutrient Profiling Systems

The basic metric produced by a nutrient profiling system can generally be applied to a single serving of one food, and then compared to a serving of other foods, or a 100-calorie portion of different foods, or a given volume of food (e.g., a 100-gram serving). These different ways to compare the nutrient content of foods tend to favor some classes of foods over others. Two examples follow.

When comparing foods via equal, 100-gram servings, all dried foods, or foods that lack moisture content, will score relatively high in nutrient content per gram, whereas foods containing a lot of moisture tend to score lower, because water is heavy.

Foods that have few calories per gram or serving, like leafy greens or onions, score very high when nutrient profiling system results are expressed per 100 or 1,000 calories, whereas calorie-dense foods, like oils, score poorly.

nutrition_label

Nutrition labels provide basic nutrition information.

Some food companies are adopting new front-of-label messaging based on rankings from a nutrient profiling system, and several retailers are working on new systems for application to their house brands.

M2M will profile and contrast today’s most widely used nutrient profiling systems, and support an M2M-developed and sponsored, open-access nutrient profiling system.

Our system will quantify the relative nutritional quality of food and encompass single-ingredient foods (an apple vs. an orange or carrot), multiple ingredients foods (pepperoni pizza, a Big Mac, yogurt with fruit), and/or daily meals.

Quantifying the Impact of Plant Genetics and Production Systems

None of the currently utilized nutrient profiling system takes into account the impact of crop genetics or production systems on nutrient density. M2M will develop methods to take these and other critical factors into account. Our first priorities will include:

  • Assessing changes in the nutritional quality of new heirloom wheat cultivars under development at WSU.
  • The omega-fatty-acid related benefits of organic dairy production, and emerging soybean and oilseed varieties (both conventionally bred and genetically engineered).
  • Methods to boost the lycopene and resveratrol content, and antioxidant activity, of fruits and vegetables and processed fruit and vegetable products.

A New Metric to Help Promote Food Security

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Diversified, multi-crop systems are often able to produce more “Human Nutrition Units” per hectare than single-crop systems. Photo by Konstantin Krismer, CC BY 3.0.

A third nutrition-related priority will be applying the M2M nutrient profiling system to calculate the “human nutrition units” (HNU) produced per acre/hectare under alternative farming systems and cropping patterns.

The approach is simple. First we will calculate the “human nutrition units” per pound or 100 grams of a given food, as typically consumed, and then multiply this value by the pounds/grams of the food produced per acre in a given farming system. For diversified farming systems producing more than one edible crop per acre/hectare, we will add the HNUs across each edible foodstuff.

Typical food waste as a raw commodity moves from storage to consumption can easily be taken into account in estimation of HNUs.

We will develop, refine, and apply the “human nutrition unit” concept to provide science-driven answers to questions like:

  • Will genetically engineered Golden rice or conventionally bred high-vitamin A corn more effectively boost Vitamin A intakes in Africa?
  • Can indigenous fruits and vegetables compete with modern varieties of corn, rice, and wheat in promoting food security via maximizing HNUs produced and consumed per acre?
  • Is there a nutritional case for classifying a slice of pizza as a serving of vegetables in the school lunch program?
  • Do intensive agricultural systems based on monocultures and specialization, or diverse, multi-cropping systems grounded in agroecology have the greatest potential to contribute to sustainable food security via maximizing HNUs per unit area in crop production?

 

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