Building a better nutrient density index

In this article I wanted to look back at nutrient density index of foods from various sources and engineer a better approach for looking at nutrient density.

Nutrient dense foods can increase satiety by providing adequate nutrition and reduced cravings with less energy.

Some approaches to nutrient density focus on vitamins and minerals while others use a broader range of nutrients that include essential amino acids and essential fatty acids.

This article outlines a new system for prioritisation of foods that focuses on essential nutrients that are more difficult to obtain.

why nutrient density matters

Dr Joel Fuhrman has done some great work developing and testing his dietary approach based on high nutrient density foods.[1]

Fuhrman’s research suggests that a high nutrient density approach (HND) to food selection leads to a range of benefits including improved:

blood sugar control,

weight loss,

blood pressure, and

blood markers.[2]

People following a high nutrient density approach tend to feel more satiated with fewer calories and are able to skip meals more easily.[3]

Harvard researcher Dr Christopher Gardner has also shown the benefits of a high fibre, nutrient dense dietary approach with his recent paper Weight loss on low-fat vs. low-carbohydrate diets by insulin resistance status among overweight adults and adults with obesity: A randomized pilot trial.[4]

In this study all participants were encouraged to eat nutrient dense, higher fibre, unprocessed foods. While the participants who were insulin resistant benefited more from a low carbohydrate approach and insulin sensitive people benefited more from a low energy density / low fat approach, everyone lost weight and improved their blood markers without having to consciously count calories!

calories and nutrient density?

It’s generally accepted that people will lose weight if they consume less calories, however the real challenge is managing appetite in the long term.

“Appetite is a dragon. Losing weight is brutally tough. Harder than particle physics.”

says RD Dikeman (pictured) who has made some great progress via tight blood glucose control (using the process outlined in the article how to use your blood glucose meter as a fuel gauge), avoidance of processed carbs and intermittent fasting.[5]

Most people find that appetite and metabolism win out over willpower or conscious calorie counting in the long run. Either we end up binging on the foods we were craving or our metabolism slows down to cope with the reduced energy intake.[6]

But what if satiety is influenced by the quantity of nutrients rather than the calories in our food? Paul Jaminet in his Perfect Health Diet books says:

“A nourishing, balanced diet that provides all the required nutrients in the right proportions is the key to minimising appetite and eliminating hunger at minimal caloric intake.”

But how do we know if we are getting the required nutrients in the right proportions? Which foods will help us maximise our chance of achieving nutrient density while minimising energy?

The chart below (click for a larger image) shows the percentage of the recommended daily reference intake (DRI)[7] of the various nutrients that you would obtain if you ate a little bit of ALL of the 7000+ foods in the USDA foods database.

Without following any particular dietary approach it seems from this that it’s fairly easy to obtain the recommended amounts of most of the amino acids, iron, phosphorus, selenium, niacin and Vitamin B-12.

However, without paying attention to the nutrient density of your diet or supplementation you will have to consume well beyond 2000 calories to obtain the recommended daily intake of calcium, magnesium, potassium, copper, vitamin E, vitamin D, pantothenic acid, choline and the essential fatty acids EPA and DHA.

Satiety is a complex and controversial topic. There are many factors including, palatability, mouth feel, smell, protein, fibre, mood, insulin resistance etc etc etc. Obtaining adequate nutrients may not be the only thing that influences appetite, but it just might be a significant piece of the complex puzzle. As you will see below, nutrient dense foods are typically also unprocessed whole foods that you would be less likely to binge on than a packet of Pringles, pizza and a bottle of coke (i.e. ‘foods with no brakes‘).

The slide below from a presentation by Bruce Ames demonstrates that there might be some room for improvement in the nutrient density of most people’s diets.[8]

This slide shows how many people are lacking in a range of key micro-nutrients. Very few people are getting adequate omega-3 essential fatty acids.

limitations of daily reference intake values

The daily recommended intake (DRI)[9] values are typically conservative. You may do fine with much lower levels than the recommended intake levels. The only way to really know if you are lacking in a particular nutrient would be to get blood tests to see if you are deficient in any nutrients.[10]

In lieu of regular blood testing of all the essential nutrients you can use the DRI values as a guide to understand if you are getting a ‘balanced diet’ with adequate amounts of the essential nutrients. Some people use apps like cronometre to see if they are meeting their minimum levels of various nutrients, but how do you know which foods will give you the best chance of maximising your nutrition?

There are meal replacement shakes (e.g. Soylent, Optifast, Ambronite etc) that enable you to theoretically meet the DRI values with a minimum amount of calories. However the safest approach is probably going to be to focus on nutrient dense unprocessed foods that contain all the essential nutrients that we know about as well as the other nutrients that we don’t yet know about.

Your metabolism may not have read the World Health Organisation’s research on the daily reference intake of the various nutrients however, if appetite is at least partially driven by obtaining adequate nutrition you can see why we are less likely to binge on nutrient dense whole foods.

The slide below from Bruce Ames shows the commonly accepted essential vitamins, minerals, amino acids and fatty acids that we require.

How to calculate nutrient density

Calculation of nutrient density is far from a precise science. Different people have taken different approaches and arrived at different food rankings.

Joel Fuhrman’s take on nutrient density uses vitamins and minerals with no consideration of amino acids or fatty acids. Fuhrman’s ANDI index also includes phytosterols, glucosinolates, angiogenesis inhibitors, organosulfides, aromatase inhibitors, resistant starch, resveratrol and Oxygen Radical Absorbance Capacity (ORAC) in the scoring. These additional parameters are not available in the USDA food database and are not part of the generally accepted list of essential nutrients, so it’s hard to include them in a comprehensive analysis.[11] The highest scoring foods with or without these additional parameters are similar (i.e. green leafy veggies) so I don’t think omitting these parameters will materially change the overall outcome.

Based on his analysis Fuhrman recommends a diet high in vegetables and fruit with a minimum of animal products and processed carbohydrates. Fuhrman recommends eating animal products only occasionally, ideally fish to provide omega 3 fatty acids. It’s not hard to see how restricting yourself to non-starchy veggies would help you to reduce your energy intake.

More recently Dr Mat Lalonde developed an alternative approach to analysing nutrient density which also includes essential amino acids and essential fatty acids. With the inclusion of animal products this approach tends to prioritise high protein animal based foods. Lalonde’s approach is based on nutrients per weight of food which may be useful for an athlete wanting to quickly refuel, however Fuhrman’s nutrietns per calorie may be more useful for someone wanting to lose weight.

The low carb community’s criticism of Fuhrman’s approach is that it is too high in carbohydrates and that it is unnecessarily biased towards plant based foods. Meanwhile the vegan community’s criticism of Lalonde’s approach is that the higher protein and fat levels are unnecessary and even dangerous.[12] They claim you can get adequate amounts without going out of your way to make it a priority.

As detailed in the optimal foods for different goals I previously had a go at developing a nutrient density ranking system that includes forty three (43) beneficial nutrients including vitamins and minerals as well as beneficial amino acids and fatty acids. While this ‘belt and braces’ approach to nutrient density will ensure that you maximise the nutrient density of your food there is also a risk that it will prioritise nutrients that are easy to obtain at the expense of nutrients that are less common in our food system.

So which approach is optimal? Vitamins and minerals only, all beneficial nutrients, or perhaps something else? Which approach will enable you to obtain a nourishing, balanced diet that provides all the required nutrients in the right proportions to minimise appetite and eliminate hunger with a minimal caloric intake.

comparison of approaches to nutrient density

The chart below (click for a larger image) compares the nutrients we obtain for the following approaches:

all foods,

top 500 foods prioritised using vitamins and minerals, and

top 500 foods prioritised using all 43 beneficial micro-nutrients.

We can see from this analysis that:

Following either approach to maximising nutrient density provides an immense improvement compared to the average of all of the foods in the USDA database.

The vitamins and minerals only approach does better in terms of most of the vitamins and minerals.

The most nutrient dense approach using forty three micro-nutrients does better when it comes to amino acids (protein), essential fatty acids (DHA and EPA), vitamin B-12, zinc, selenium and niacin.

There is a lot of variability in the amounts of nutrients in terms of percentage of the DRI.

So if our goal is to avoid malnutrition with the minimum amount of calories, which approach is optimal?

Perhaps what we need, rather than amplifying all nutrients, is to prioritise the foods with the nutrients that are harder to obtain?

removing the overachievers for a better nutrient density index

The chart below shows the proportion of the population that consume less than the recommended amount of various essential nutrients. From this it seems we should, as a minimum, prioritise vitamin D, vitamin E, magnesium, calcium, vitamin A and vitamin C.

Starting with the full list of forty-three beneficial nutrients I have progressively removed the ‘overachievers’ so we only prioritise the harder to obtain nutrients. The nutrients that you could obtain more than 500% of the daily recommended intake (DRI) with 2000 calories have been removed from the system.

I have also removed the fatty acids that could be considered contentious in a minimalist food ranking system. So rather than 43 nutrients we end up prioritising only the 27 hardest to obtain essential nutrients.

vitamins

Choline Thiamine Riboflavin Niacin Pantothenic acid Vitamin A Vitamin B12 Vitamin B6 Vitamin C Vitamin D Vitamin E Vitamin K

minerals

Calcium Copper Iron Magnesium Manganese Phosphorus Potassium Selenium Sodium Zinc

amino acids

Cysteine Isoleucine Leucine Lysine Phenylalanine Threonine Tryptophan Tyrosine Valine Methionine Histidine

fatty acids

Docosahexaenoic acid (DHA) (22:6 n-3) Eicosapentaenoic acid (EPA) (20:5 n-3) Docosapentaenoic acid (DPA) (22:5 n-3) Alpha-linolenic acid (18:3 n-3) Arachidonic acid (20:4) Oleic acid (18:1) Lauric acid (12:0) Capric acid (10:0) Pentadecanoic acid (15:0) Margaric acid (17:0)

The chart below (click for larger image) shows the outcome of the moderated approach compared to the other approaches (i.e. all foods, vitamins and minerals only and all 43 nutrients). A number of the nutrients that were lower using the “all nutrients” approach have improved (i.e. calcium, magnesium, vitamin A, vitamin C, selenium, vitamin E and vitamin D).

which nutrient density index is better?

The moderated approach does pretty well across the board. The problem is that it’s hard to make sense of all this data to confirm which approach is optimal. How do we simplify the decision process?

In engineering we often think in terms of reliability statistics.[13]

Let’s say Acme brand widget is really strong on average but highly variable. If you buy a box of Acme widgets most of them will be strong, but you might get some low strength duds. Acme of widget not reliable so we have to be conservative when it comes to the design assumptions. In the design we might assume that a widget is only as strong as the average minus one or two standard deviations of the strength to make sure our design is conservative.

However if we can decrease the variability by improving the manufacturing process and produce a box of widgets that are not quite as strong on average but less variable we can assume a lower factor of safety and assume more capacity in a design using that bolt.

Perhaps we can use a similar analysis approach when it comes to nutrient density. What we ideally want is a diet that has high levels of all of the essential nutrients without any nutrient deficiencies that would require supplementation.

The chart below plots the average of all the nutrients as a proportion of the DRI (blue bars). We can see that all three approaches to ranking nutrient density do better than the average of all foods in the USDA database, with the “43 micro-nutrients” approach scoring the best. However we know from the chart above that this high score is largely due to very high amino acid scores for the “all 43 micro-nutrients” approach.

The vitamins and minerals only approach also does well, however we also know that this is due to the higher score in the vitamins and minerals with lower scores in some of the other nutrients such as the proteins and essential fatty acids.

The orange bars in the plot represent the average minus 0.8 times the standard deviation of the nutrients as a percentage of the DRI requirement. Using this approach to comparison it appears that the moderated nutrient density approach is better because we have less variability across the nutrients, with some lower highs and lots of higher lows compared to the other approaches.

What this means in practice is that the moderated approach will more reliably provide you with the essential vitamins, minerals, amino acids and fatty acids that you require without needing to supplement or overeat to provide the missing nutrients. The moderated nutrient density approach seems to give us a better outcome in terms of nutrient density.

most nutrient dense foods

Listed below is a summary of the top 1000 foods prioritised by the moderated nutrient density index detailed above.

In addition to nutrient density score (note: 0 is average and a score of 2 means that a food is two standard deviations above the mean) I have also included a number of other parameters that may be of interest.

The percentage of insulinogenic calories and net carbs per 100g of food will be of interest for someone who aiming for a high fat therapeutic ketogenic diet.

calories and net carbs per 100g of food will be of interest for someone who aiming for a high fat therapeutic ketogenic diet. The insulin load may be of interest for someone who is insulin resistant and wanting to consume a diet that their pancreas can keep up with.

may be of interest for someone who is insulin resistant and wanting to consume a diet that their pancreas can keep up with. Net carbs will be useful for someone doing standard carbohydrate counting.

will be useful for someone doing standard carbohydrate counting. The energy density (calories per 100g) will be of interest for someone looking to decrease the energy density of their diet for weight loss.

I have also shown the vitamin, mineral and protein plots for some of the highest ranking foods in each category to get a feel for the nutrition provided by each of these foods.

Choosing nutrient dense whole foods typically ensures that the other relevant parameters are favourable, though these other factors may be of interest depending on your situation.

Future articles will look at how we can fine tune our food selection to suit people who are insulin resistant and wanting to normalise their blood glucose levels or who are insulin sensitive and still looking to lose weight. In the meantime you can check out these summary food lists that are based around these ideas:

nutrient dense vegetables

If you look down the nutrient density (ND) scores of all the foods you will see that the vegetables do really well compared to the other food groups. If you were aiming to maximise nutrient density you could simply focus on eating as many vegetables as you could with perhaps some supplemental seafood for essential fatty acids.

Celery tops the list of nutrient dense dense foods because it has a lot of vitamins and minerals with very few calories. The chart below from Nutrition Data shows that we would obtain 81% of our required vitamins and minerals from 1000 calories and 52% of the protein. The is that we would need to eat 100 celery stalks to obtain that 1000 calories! However you can see how in terms of nutrients per calorie celery is amazing and you wouldn’t go wrong trying to fill up on these high nutrient density low calorie density foods.

food ND % insulinogenic net carbs/100g insulin load (g/100g) calories/100g celery 2.63 49% 1 2 17 rhubarb 1.46 57% 3 3 21 turnip greens 1.31 39% 1 4 37 lettuce 1.34 52% 2 2 17 winter squash 1.22 80% 7 8 39 broccoli 1.21 57% 4 6 42 asparagus 1.12 46% 2 3 27 Chinese cabbage 1.02 60% 1 2 16 summer squash 1.00 65% 2 3 19 okra 0.94 57% 4 5 37 bamboo shoots 0.90 52% 3 4 28 bell peppers 0.86 64% 6 7 43 artichokes 0.83 33% 3 4 54 cabbage 0.81 53% 3 4 30 kale 0.75 74% 8 10 56 parsnip 0.73 38% 7 7 76 seaweed (kelp) 0.74 43% 4 5 50 snap green beans 0.74 47% 4 5 40 peas 0.69 58% 5 7 51 radishes 0.70 50% 2 2 19 mushrooms 0.65 70% 2 5 30 sweet potato 0.51 82% 17 18 87 onions 0.52 77% 7 8 41 jalapeno peppers 0.52 54% 4 5 35 pinto beans 0.44 60% 16 21 142 sweet corn 0.43 47% 10 13 111 collards 0.44 46% 2 5 40 dill 0.42 30% 2 4 52 eggplant 0.39 67% 7 7 41 beets 0.34 44% 4 5 48 shallots 0.27 60% 46 56 377 mung beans 0.33 46% 1 3 26 thyme 0.27 21% 14 19 359 black pepper 0.24 36% 24 29 327 bay leaf 0.21 37% 34 38 406 chives 0.27 34% 1 3 37 mustard greens 0.27 45% 2 3 30 Brussels sprouts 0.24 54% 5 7 52 shiitake mushrooms 0.20 68% 51 59 349 paprika 0.19 17% 8 16 389

nutrient dense fruit

The list of nutrient dense fruits is shorter than the vegetables due to the higher amount of calories and sugar in proportion to the amount of nutrients.

The plot below shows that we get 57% of the vitamins and minerals and 44% of our protein from 1000 calories of mandarin orange.

food ND % insulinogenic net carbs/100g insulin load (g/100g) calories/100g cherries 0.72 84% 10 11 54 orange 0.49 77% 10 11 55 apples 0.48 77% 10 10 53 grapes 0.45 80% 15 15 77 figs 0.37 81% 16 17 82 blueberries 0.32 72% 16 16 91 mandarin oranges 0.31 63% 9 9 59 honeydew melon 0.30 88% 8 9 40 passion fruit 0.24 54% 13 15 109 raisins 0.20 84% 68 70 336 litchis 0.20 80% 14 15 73 dates 0.17 72% 54 56 308

nutrient dense legumes

Legumes tend to have a higher energy density than the vegetables and thus may be useful if you need some more calories to support your activity and can’t fit in any more celery, lettuce and broccoli.

The Nutrition Data plot below for lentils shows that 1000 calories will provide 58% of your vitamins and minerals and 86% of your protein.

food ND % insulinogenic net carbs/100g insulin load (g/100g) calories/100g lima beans 0.56 71% 16 23 129 navy beans 0.47 55% 15 20 143 lentils 0.35 62% 12 18 118 hummus 0.26 32% 8 14 175 peanuts 0.17 18% 7 28 605

nutrient dense grains

The nutrient dense grains tend to be the least processed. Unfortunately most grains are consumed in a highly processed form.

The plot below shows that oats will give us minerals and a substantial amount of protein, but are not as high in the vitamins compared with a number of the other foods.

food ND % insulinogenic net carbs/100g insulin load (g/100g) calories/100g oatmeal 0.77 58% 8 10 67 teff 0.70 54% 11 14 101 spelt 0.58 54% 14 18 135 rice noodles 0.54 87% 22 23 105 quinoa 0.45 55% 14 16 120 oat bran 0.35 57% 29 38 264 millet 0.34 76% 20 22 118 rye bread 0.30 64% 37 45 282 rice bran bread 0.25 54% 31 37 273 wheat bran bread 0.24 68% 37 44 257 oat bran muffins 0.23 48% 29 35 288

nutrient dense dairy and eggs

The nutrient density score for eggs and dairy is not as high as the vegetables, however the proportion of insulinogenic calories and net carbohydrates is lower which will mean that these foods have a minimal impact on blood glucose levels.

The plot below shows that we would get half of our required vitamins and minerals and 136% of our protein requirements from 1000 calories of eggs (i.e. 14 eggs).

food ND % insulinogenic net carbs/100g insulin load (g/100g) calories/100g parmesan cheese 0.18 30% 3 31 411 goat cheese 0.17 22% 2 25 451 edam cheese 0.17 22% 1 20 356 gruyere cheese 0.17 21% 0 22 412 Swiss cheese 0.17 26% 5 25 379 egg yolk 0.17 19% 4 15 317 gouda cheese 0.17 23% 2 20 356 provolone 0.17 24% 2 21 350 blue cheese 0.16 20% 2 18 354 cheddar cheese 0.15 20% 1 20 403 limburger cheese 0.16 18% 0 15 327 camembert cheese 0.16 20% 0 15 299 Monterey 0.15 20% 1 19 373 muenster cheese 0.15 20% 1 18 368 Colby 0.15 20% 3 20 394 whole egg 0.16 29% 1 10 138

nuts and seeds

Nuts and seeds are more energy dense but lower in carbohydrates due to their higher fat content. While nuts and seeds will help someone achieve more stable blood glucose levels it is common knowledge in low carb circles that you need to watch your intake of nuts, seeds and dairy if you’re trying to lose weight.

food ND % insulinogenic net carbs/100g insulin load (g/100g) calories/100g coconut water 1.51 66% 3 3 20 sunflower seeds 0.18 20% 11 24 491 tahini 0.17 16% 13 26 633 pine nuts 0.16 11% 9 18 647 pecans 0.15 5% 4 9 762 pistachio nuts 0.16 23% 19 34 602

seafood

Omega 3 fatty acids are important but hard to get in the diet, so it’s worth going out of your way to ensure you are getting enough.

The plot below shows that we can get more than half of our vitamins and minerals and 148% of our protein requirements from 1000 calories of sardines.

food ND % insulinogenic insulin load (g/100g) calories/100g anchovy 0.34 42% 21 203 caviar 0.30 32% 22 276 tuna 0.30 50% 17 137 oyster 0.31 57% 14 98 rainbow trout 0.28 43% 17 162 mackerel 0.28 45% 17 149 swordfish 0.28 41% 17 165 lobster 0.30 69% 14 84 herring 0.26 34% 18 210 salmon 0.28 50% 15 122 whitefish 0.27 67% 17 102 octopus 0.26 69% 27 156 halibut 0.27 63% 16 105 Pollock 0.27 66% 17 105 sturgeon 0.26 47% 15 129 sardine 0.24 36% 18 202 shrimp 0.26 66% 19 113 crab 0.26 69% 13 78 snapper 0.25 64% 15 94 haddock 0.24 67% 18 110 mussel 0.22 61% 25 165 whiting 0.21 63% 17 109 crayfish 0.21 64% 12 78 abalone 0.21 76% 19 99 haddock 0.21 69% 15 85 clam 0.20 71% 24 135

animal products

When it comes to animal products the lower fat cuts tend to rank higher when it comes to nutrient density.

Liver ranks the highest overall and the vitamin and minerals score as well as the protein score is substantial.

food ND % insulinogenic insulin load (g/100g) calories/100g beef liver 0.46 58% 24 169 chicken liver 0.43 48% 20 165 ham 0.26 55% 20 146 pork 0.25 54% 21 154 veal (leg) 0.25 56% 25 174 emu 0.24 63% 25 159 beef 0.22 50% 25 197 chicken breast 0.22 56% 25 178 turkey breast 0.22 70% 22 127 bacon 0.18 23% 30 522 ground turkey 0.19 37% 19 203 ostrich 0.19 46% 19 168 veal (sirloin) 0.18 38% 19 195 pork 0.18 46% 21 182 chicken drumstick 0.17 36% 22 238 goose 0.17 37% 21 230 duck (meat only) 0.17 36% 17 195 beef steak 0.16 28% 21 305

Should everybody eat just these nutrient dense foods?

As a general rule most people would do well eating from this list of nutrient dense whole foods. Unprocessed nutrient dense foods would be a major improvement for most people. There is however opportunity to further refine this for specific goals such as weight loss or diabetes.

In future articles we will look at how we can use the concepts of energy density and insulin load to further refine this list for people who are looking to lose weight and for people who have diabetes and need to control their blood glucose levels. In the mean time you may be interested in these summary food lists:

references

[1] http://www.wholefoodsmarket.com/healthy-eating/andi-guide

[2] https://www.drfuhrman.com/members/m_library/OJPM20120300014_73341742.pdf

[3] https://www.drfuhrman.com/library/changing_perceptions_of_hunger.pdf

[4] http://onlinelibrary.wiley.com/doi/10.1002/oby.21331/full

[5] RD also happens to be a physicist and a chief scientist with defence contractor Lockheed Martin. He is also an admin on the TYPE ONE GRIT facebook group for people with type 1 diabetes (his son has type 1 diabetes) and produces Dr Bernstein’s Diabetes University.

[6] http://www.amazon.com/Obesity-Code-Unlocking-Secrets-Weight/dp/1771641258

[7] https://ods.od.nih.gov/Health_Information/Dietary_Reference_Intakes.aspx

[8] https://www.youtube.com/watch?v=ZVQmPVBjubw

[9] http://www.mydailyintake.net/nutrients/

[10] http://www.lifeextension.com/vitamins-supplements/blood-tests/nutrient-testing

[11] http://www.wholefoodsmarket.com/healthy-eating/andi-guide

[12] http://www.vegsource.com/articles/protein.danger.htm

[13] https://en.wikipedia.org/wiki/Reliability_(statistics)

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