What is nutrient density?
Nutrient density identifies the proportions of nutrients in foods. By nutrients, I refer to vitamins, minerals, amino acids, and fatty acids.
Before jumping into the analysis we need to identify commonly accepted essential nutrients that can be found in USDA database. Luckily, USDA food database has information about most of the essential nutrients.
- Vitamin A
- Vitamin E
- Vitamin D
- Vitamin C
- Vitamin K
- Thiamine (B1)
- Riboflavin (B2)
- Niacin (B3)
- Pantothenic acid (B5)
- Vitamin B6
- Vitamin B12
Essential Amino Acids
Essential Fatty Acids
How to calculate nutrient density for individual nutrients in foods?
In order to find the best method to calculate nutrient density for individual nutrients in foods we need to take a look at the end result that we are trying to achieve.
We want to have a combined nutrient density from all nutrients for each food.
It seams not feasible because each nutrient could be represented in milligrams, grams, micrograms, or even IUs.
Each nutrient also has a specific Daily Recommended Intake value.
Turns out we can compare apples and oranges...
The best scientific approach here will be to convert each nutrient value to a standard score.
Standard Score Formula
Z = (X - mean of population) / standard deviation of population
I want to find Nutrient Density (ND) of Selenium in Oysters.
Let's apply our formula.
ND of Selenium in 1 gram of Oyster is our Z.
X is the amount of Selenium in Oysters per gram.
Mean of population is the average of amounts of selenium per gram in all foods.
Standard deviation of population is standard deviation of amounts of selenium per gram in all foods.
Now, I did this analysis on all essential nutrients for all foods in USDA database both for nutrient density per calorie and nutrient density per gram.
That is a lot of reliable data...
We can do a lot of fun stuff with this data. One of my favorite tools that I created is Nutrient Explorer. It is the only tool on the web that can reliably generate food lists, based on what nutrients you want to maximize or minimize.
How to calculate nutrient density for a specific food.
Sum of individual ND scores depending on your dietary goal.
For example, if I want to maximize Choline, Vitamin D, and Omega-3, then nutrient density for foods would be the sum of individual nutrient densities (Choline, Vitamin D, and Omega-3) for each food and then ranking foods based on scores.
Nutritiousness Score For Foods:
Our nutritiousness score is defined by summing all individual nutrient densities per calorie of harder to find nutrients for each food and finding the minimum and maximum score in ~8900 USDA food database. It guarantees to find the best foods to maximize all nutrients.