Defining Powerhouse Fruits and Vegetables: A Nutrient Density Approach | Hacker News Reader

Defining Powerhouse Fruits and Vegetables: A Nutrient Density Approach

cdc.gov

46 pointsrottyguy25 comments

The submission title is a little misleading. The article does not indicate that these foods have been linked to reduced chronic disease, but

1. Studies have linked several nutrients to protection against chronic disease, and

2. The article has identified these foods as being rich in those nutrients.

Not following your distinction. Are you intimating that b/c the nutrients are in these foods, they might not be absorbed correctly and therefore it would diminish their benefits? (btw- the title was taken almost verbatim from the text)

I think post is pointing out that the foods haven't been tested to reduce chronic disease directly. The assumption that they would is because they have certain nutrients, and consumption of those nutrients has been associated with a risk reduction.

BWT, density can be defined as nutrients per kg or per cal, when defined per cal this is what you get.

It's easy to say that if you eat a serving of X food every single day you'll get enough of a specific nutrient. It's not easy to eat a serving each of A,B,C...J foods every single day. You can't ignore the need to remove other nutrient-containing foods to stay within your calorie budget. That's the difference between 'nutrients' and 'food with nutrients'.

Yeah the title should be something like "Study identifies the most nutrient-dense foods". Of course, I doubt that would get upvoted as much.

This submission broke the HN guidelines, which say to use the original title unless it is misleading or linkbait.

We missed this one because of the "occasional evening off" bug.

(Submitted title was "Foods most strongly associated with reducing chronic disease risk".)

I'd like to see another table normalized by serving size. Eating 100g of watercress is a lot different from 100g of sweet potato.

Yeah, watercress is much nicer. You can make it into soup too...

Surprised to see sweet potatoes at the bottom. A study linked from wikipedia [1] indicates that sweet potatoes ranked #1 in nutritional density. Not sure where that study is. I did find one where they are ranked 8th [2]

Whatever, I eat ~1 a day because they're incredibly delicious, cheap and easy to cook.

[1] http://en.wikipedia.org/wiki/Sweet_potato#Nutrient_content

[2] https://www.cspinet.org/nah/01_09/ratings.pdf

It's because of the nutrients they pick, which they then use an unjustified weighting trick to make sure that only foods with high levels of Vitamin C, Riboflavins, and/or B6 meet the grade. This methodology then rules out onions, garlic, and a few others, finding that (by using these weightings), they are without sufficient nutritional merit.

I think it's actually because they're measuring nutrients per calorie instead of measuring nutrients per serving or nutrients per weight. The linked chart above[1], on page 15, gives sweet potatoes a rating of 485 for 100 calories, and tomatoes (way farther down the list) a rating of 134 for 20 calories. Normalize to 100 calorie "servings" and tomatoes go up to 670! But that's something like 1/2 kg of tomatoes right there, and you'd be sick of it.

[1]: https://www.cspinet.org/nah/01_09/ratings.pdf

I agree that nutrients per calorie is also part of it, which is an unusual metric as was pointed out. The bioavailability metric is just plain cheating (or poor math) though since bioavailability is already factored into percent daily value figures.

Also, with the sweet potatoes, their vitamin C levels go up by a factor of 8 when cooked, which would rank them much higher on the list. Not many people eat sweet potatoes raw so whether it's good science to assume that they do is reasonably debatable.

I think this is a great start. I love studies that (a) cite quality sources, but (b) leave you with more questions than answers. I know - we all love to have everything tidily rapped up in a five paragraph article but hey: new studies beget more new studies and those new studies hopefully will answer questions like:

* It says, "Because preparation methods can alter the nutrient content of foods (2), nutrient data were for the items in raw form." Would love to see this compared to the results after "common cooking and preparation methods"

* Can we compare this to serving size next?

* What are the nutrient densities of, say, beef? chicken? Pork? Rice? Noodles? etc (other staples of many diets)

Interesting info, but I feel like these studies serve to reenforce the contemporary attitudes of certain foods being "magical" and food as "medicine".

In a world where 100 million americans are obese and another 100 million overweight, these foods are definitely magical.

Those are some terrifying numbers...

I don't follow. How do zinc and riboflavin affect calorie intake?

They have the benefit of being plants, but so do hundreds of things that didn't make the list...

Note that the ones at the top of the chart can be eaten raw. Some at the bottom must be cooked.

Are foods that we could eat before we invented fire better for us?

No, foods that don't contain anything we need to survive are good for making us live longer is the only conclusion you can draw from this list.

Sad not to see watermelon or mango in that list of powerhouses.

Fruits stand little chance against vegetables in a list where the score is divided by the amount of calories. It also makes this list absolutely useless, as calories are absolutely irrelevant in a nutrient density ranking.

A kg of watercress has more nutrients than a strawberry, are we all surprised?

I like how they leave out potatoes because of keto mythology claiming they are just starch with no nutrients. I guess all that potassium, vitamin C, B6, niacin, folate, iron, etc. doesn't count because reasons.

What? Are you just making stories up for some reason?

Based on http://nutritiondata.self.com/facts/vegetables-and-vegetable... for a raw potato, the 17 nutrients involved total 363% daily value per 284 calories, so normalizing by dividing by 2.84 and 17 gets a final score of 7.5. Potato is not a powerhouse. Oh and I neglected to factor in bioavailability which would make that number even smaller.

All those nutrients you mention 'count', but there's only a large supply of potassium, C, and B6. Three out of seventeen is a pretty bad score.

If you follow that same methodology, none of the scores they listed are accurate. 1 out of 17 is even worse than 3 out of 17, and yet they inexplicably have iceburg lettuce at 18.28.

Iceburg lettuce, let's see.

http://nutritiondata.self.com/facts/vegetables-and-vegetable...

Remember that the par value is 10% daily value per nutrient per 100 calories. This is for only 10 calories, so anything at 1% or greater is a good supply.

The nutrients measured: potassium, fiber, protein, calcium, iron, thiamin, riboflavin, niacin, folate, zinc, and vitamins A, B6, B12, C, D, E, and K

In order lettuce has: lots, lots, par, par, lots, lots, par, none, lots, par, lots, lots, none, lots, none?, par, massive

Again I'm ignoring bioavailability but 18 looks about right once that factors in. Lettuce has most of the nutrients desired per calorie. Not just one.

edit: fixed b6 and b12. And I hope whoever downvoted my first comment replies saying why...

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