The Return of NNR Food Scores (L-O-N-G)

Back in 2005, I wrote an article on a new method of scoring food for nutritive value-the NNR, or Naturally Nutrient-Rich. Recently, I came across a follow-up and explanation of that method.

From the North Jersey Herald: “Generally, the energy density of a food is a function of its water content, says Adam Drewnowski, Ph.D., a researcher at the University of Washington. Foods with high water content (which generally have high fiber content) tend to have a low energy density and can fill you up without making you fat. The key is to feel full on fewer calories so that you don't consume more than your daily calorie budget.

Studies show we're satisfied as long as the portions we eat are the "right" volume -- meaning the same size as what we would normally eat. Therefore, eating a diet rich in low-density foods allows you to eat a lot, but it won't cost you too many calories. Plus, those eating a low-energy-dense diet generally have higher intakes of several significant micronutrients.

Drewnowski has developed a scoring system called the Naturally Nutrient Rich (NNR) score to help consumers identify nutrient-rich foods. It identifies the nutrient-to-calorie ratio of foods and is based on 16 nutrients: protein, calcium, iron, vitamin A, vitamin C, thiamine, riboflavin, vitamin B12, folate, vitamin D, vitamin E, monounsaturated fat, potassium, zinc, fiber and vitamin B5. To get an NNR score for a serving of food you add up its percentage of Daily Values (the nutrients contained in a single serving as compared with the recommended daily intake of that nutrient) and then divide it by the number of nutrients used (16). It ranges from 2 to 1,000. According to Drewnowski, anything over 100 is good; anything over 250 is excellent; and there are some scores in the stratosphere -- specifically fruits and vegetables. Whereas jelly beans have a score of 3 and lard has a score of 35.

By assigning values based on multiple nutrients, healthful foods are defined by beneficial nutrients rather than simply the absence of fat, sugar or salt.
Food is about more than just calories. There are many components, and nutrient-density ratings can help consumers make better food choices.

Unfortunately, it doesn't account for the bioavailability of the nutrients, the freshness or organic nature of the food or the importance of antioxidants.

It's not easy to determine the nutrient density of the foods you eat -- there is not one location of this information yet. However, if you look for fruits and vegetables, whole grains, low-fat and nonfat dairy products, lean beef and pork, skinless chicken and turkey and legumes, you'll be off to a great start.”

Common Naturally Nutrient Rich (NNR) Scores:

Fruit
NNR Score = 250 (great)
Cantaloupe, strawberries, kiwi, grapefruit, orange, mango, apricots, tangerines

NNR Score = 100-250 (good)
Raspberries, blackberries, watermelon, peaches, nectarines, pineapples, plums, avocados, blueberries
(compare canned grape juice - 33)

Vegetables
NNR Score = 1,000 (great)
Red peppers, carrots, pumpkin, spinach, romaine lettuce, mustard greens, broccoli

NNR Score = 500-1,000 (good)
Green peppers, sweet potatoes, iceberg lettuce, V-8 juice, cauliflower
(compare french fries - 50)

Meat and fish
NNR Score = 1,000 (great)
Oysters, clams, beef liver, chicken liver

NNR Score = 250 (good)
Mackerel, bluefish, lean ham, beef sirloin (lean), snapper, canned tuna

NNR Score = 100-250 (okay)
Beef chuck, salmon, lamb, pork, eggs, cod, shrimp
(compare fried chicken breast with skin - 65)

Dairy products
NNR Score = 250 (great)
Skim milk, nonfat yogurt

NNR Score = 100-250 (good)
1 percent milk, 2 percent milk, low-fat yogurt, whole milk, cottage cheese, mozzarella, reduced-fat cheddar
(compare ice cream - 50)

Grains
NNR Score = 100
Oatmeal, bagel, waffle, cereal bar
(many cereals score extremely high, but they are fortified)

*Source: Adam Drewnowski, Ph.D., director, Center for Public Health Nutrition, professor of Epidemiology and Medicine
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Wench’s notes: Obviously, this is still a work in progress. I have been in contact with Professor Drewnowski while trying to perform the above-mentioned calculations (trying to compare MY carrots to his carrots), and had some trouble achieving the 1000 NNR score. I figured either I couldn’t calculate my way out of a paper bag (typical for me), or I must be buying truly inferior organic carrots. Turns out that the math calculations stated above are for food items extrapolated out to a portion size equaling 2000 calories (done with dietician software). I was trying to do the math using “single serving size” information and not “2000 calorie” information. Professor Drewnowski says that the research team is currently working on a math formula for single serving sizes so the average consumer will be able to figure out the NNR scores of foods already in the home, as well as in the store aisles. For now, the math calculations remain a dietician’s software function (unless you feel like multiplying everything out to the 2000-calorie point). All I know is that 2000 calories’ worth of carrots would probably choke a horse, and I’m not about to start feeding horses.

In the meantime, use the list already provided as a guideline until the new formula comes out. He promises to alert me when there’s a formula.

Something you might want to consider: as I found in my experimental diet month, grains, nuts, and dairy are not really necessary to the human diet—the above NNR scores for dairy and grains prove that these foods are not really nutrient-dense at all when compared to fruits, vegetables, and meats. However, I have suggested to Professor Drewnowski that he include quinoa, amaranth, and soy beans to his research when assigning NNR scores to foods. These foods contain other nutrients besides the “starch” factors, are shelf-stable, and widely available in health food stores (sometimes in bulk).

Something I casually observed while attempting to score foods on my own: you can pretty much tell what foods are made up of just by looking at the %DV column—if there are only % numbers in the carbohydrates, sugars, and fiber rows, then the food item is pretty much starch. This food provides more energy (in calories) than nutrients. I looked at a jar of mayonnaise (eggless) and a can of kidney beans, and the kidney beans had %DV values in ten nutrients other than the usual “starch” suspects, while the mayonnaise had no nutritive %DV values besides fats. Basically, the more nutrients (vitamins and minerals) assigned a % number (other than zero) on the food label, the more nutritive the food item. The greater those % numbers are, the higher the value for that particular nutrient. Aim for the highest numbers you can find in the vitamin and mineral areas.

Why did I buy canned kidney beans instead of dry? Because they were cheaper by the pound than the organic store’s dry beans—even in bulk.

Something I did just for fun: I cross-referenced the above list with all the other lists I use for making food decisions (ORAC, TAC, and Ape Diet), and came up with these common food denominators: blackberries, blueberries, strawberries, oranges, and plums. Apparently these fruits score high as NNR foods and as antioxidant sources. This means more bang for your fruit buck while shortening the shopping list. I know it’s not exactly “eating the rainbow,” but there are always vegetables to fill in for the missing colors. As for vegetables, none were common denominators across all lists, but there was one that made a 2-out-of-3 showing: red peppers. Carrots, broccoli, and spinach made a poor showing on the TAC list (not even in the top 50 foods), but still made for a very weak 2-out-of-3. Theoretically, one could take all these foods and include them together in a salad (along with more greens, of course).

Another bonus for these "magic 5" fruits--only the blackberries and strawberries need to be organic. The rest can be bought (safely) in commercial form, because the commercial versions carry fewer pesticides than their organic counterparts.

So much for the apple a day keeping the doctor away, huh?