Sunday, July 13, 2014

Comparing Nutrient Density using the NUTTAB Nutrient Database

One of the main purposes of the nutrient database was to compare the nutrient content of foods and food groups in a meaningful way - the amount of nutrients in 2000 kcal of food divided by the RDI.  All values in this post are based on that measure 

Whole Foods are Superior 

I firstly compared categorised the groups into whole foods, SAD meals, junk foods and extras*.  It’s clear from this that whole foods on average are superior and good sources of almost all nutrients, such that simply eating a balanced whole food diet is very likely to fulfil almost** all nutrient needs and more.  There’s something to be said for ‘just eat real food’ (JERF) 

In this very rough measure, the whole food average was only lacking in fluoride (which you get in the water supply), manganese, sodium (which you can easily add to foods) and vitamin A.  Manganese is mostly found in plant foods, particularly grains.  The AI is based on the median population intake and so I think our grain-based diet skews estimates on how much manganese we need.  Vitamin A is kind of surprising, but it’s really only found in sufficient quantities in vegetables, eggs, liver, dairy and some fruits; where certain vegetables and liver are extremely good sources of vitamin A.  This might be just because I took the medians of groups rather than the mean 

The weight and macronutrients are also interesting.  Whole foods are generally high in protein and less calorie dense than SAD meals and junk food, and the SAD meals is remarkably close (by accident) to the macronutrient ratio eaten by Australians (~17:33:45).  There’s also like a gradient where protein decreases and energy density increases as foods/meals get more processed with increasing amounts of added refined sugars, starches and fats.  That being said, the averaged protein in the whole foods category is too high
* Whole foods included: dairy (average of cheese and milk), eggs, fruit, aboriginal plant foods, legumes, offal, nuts and seeds, crustacea and molluscs, vegetables and meat (which is an average of beef, game and other meat, lamb, mutton, pork, poultry, veal and fish) 

SAD meals included: bread and bread products, breakfast cereals, flours, grains and starches, hamburgers, pizza and other takeaway products, noodles and pasta, dairy and meat alternatives, processed meats, asian restaurant foods, mediterranean restaurant foods, processed fish, crustacea and molluscs and soups 

Junk foods included: biscuits, cakes, slices and other battered products, pastries, pies and tarts, ice cream & edible ice products, yoghurts and dairy desserts, snack foods, chocolate based and sugar based confectionary 

NOTE: I averaged the meats together and dairy together because there were several groups of meat that would otherwise skew the average and also by averaging the groups of meat and dairy into two groups it resulted in 5 groups of animal foods and 5 groups of plant foods.  Within these groups: ‘milk’ was more nutrient dense than ‘cheese’; and ‘game and other meat’, ‘veal’ and ‘fish’ were more nutrient dense than other meats 

** There are some nutrients that aren’t widely found in foods in sufficient quantities, such as choline/betaine 

Which Whole Foods are More Nutrient Dense? 

By using the nutrient database we can also get an idea as to which food groups are more nutrient dense, which you can see in the table below arranged from most nutrient dense to least
Obviously there are problems with calculating nutrient density this way:
  • In the USDA nutrient database the same measurements was higher but particularly for vegetables (3.5) and fruits (1.24), which seems to be due to a lot of 0’s in the raw data where you would expect there to be something
  • Values like 106.90 for B12 in offal that inflates the average, although in this comparison those really high values didn’t make much difference in the ranking (except aboriginal plant foods, see first point)
  • This doesn’t account for some missing micronutrients (choline/betaine, K1, K2), bioavailability and other nutrients/beneficial compounds in foods

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