Tuesday, September 18, 2012

Clarifying nutrition: focus on Source, Process, and Time

This table shows the antioxidant contents of 3,000 foods:

The Antioxidant Food Table

On first glance, I was annoyed, because there was so much redundancy in the foods examined: 11 entries for blackberries? Couldn't they make up their minds?

On closer inspection, a deeper story emerged. Take a look at this and see what you find:

Product Label Procured in Antiox. (mmol/100g) Prep
Blackberries, cultivated USA 4.02 6
Blackberries, cultivated Solabaer, Sola, Norway Norway 4.13 3
Blackberries, cultivated Norway 6.14 3
Blackberries, cultivated Belgium Norway 3.84 3
Blackberries, cultivated, canned, drained S&W Fine Food, USA Norway 2.34 3
Blackberries, cultivated, frozen Local grocery USA 4.06 6
Blackberries, cultivated, frozen Wholesaler USA 3.89 6
Blackberries, cultivated, with sugar Findus, Norway Norway 4.76 3
Blackberries, Dessert Berries, without sugar, frozen Norske Dessertbaer, Norway (berries from Poland) Norway 5.98 3
Blackberries, dried, "Loch Ness" The Norwegian Crop Institute Norway 37.08 5
Blackberries, wild Norway Norway 6.13 4
Comments:
...
3 Purchased in grocery store, restaurant, cafe, bakery or marketplace.
4 Handpicked or received directly from supplier.
5 Previously published in Halvorsen et al. 2002 or Dragland et al. 2003
6 Previously published in Halvorsen et al. 2006.


Notice how much variation there is?

This table indicates what's behind those eternally confusing reports about which food has the  most antioxidant activity.

With a spread of more than tenfold in the antioxidant activity in blackberries, you simply have to look at two more factors:
  • Source
  • Preparation
Understanding these two critical factors helps clarify a lot of red-herring driven confusion over which foods are most nutritious.

It's a reminder of something we know, but tend to forget in the barrage of information and anxiety around food. 
  • Plants and animals need nutrients, water, sunshine and air to grow; the quality and quantity of these things affects what they produce.
    More species-appropriate and healthful growing environments produce more nutritious food than inappropriate or unhealthful environments.
    Different strains of the same species have different attributes, as someone who has tasted longhorn steak and kobe steak side-by-side could probably tell you.
  • Food nutrients are reactive, which means that heat and light are going to make them change over time.
    If they weren't reactive, they wouldn't be nutrients, because nutrients need to be amenable to digestion and assimilation -- that is, physical and chemical reactions -- before they can do us any good.
    Therefore, food nutrients are susceptible to heat, light and time.

Source matters


Cultivated blackberries from 3 different places had an antioxidant score that varied by roughly a third. That's a significant variation!

There was only one sample of wild berries, which rated about the same as the best of the cultivated fresh berries from the same region. Wild strains of berries are generally more nutritious, so it should be said that this study does not specify if these berries were from a wild strain, or from a cultivated strain found growing in the wild. Not everyone realizes there's a difference, but heredity matters (kobe/longhorn.)


Preparation matters

Processing makes a huge difference in the amount of nutrition available per, say, 100 grams.

Notice how the canned berries, which are subjected to considerable heat in the canning process, have the least antioxidants.

The frozen berries, which are meant to last awhile (thus being subject to time) have less bounce per ounce than some, but more than the canned berries.

The fresh Norwegian berries that travelled to Belgium are likewise impoverished, and the distinguishing factor between them and the Norwegian berries in Norway is the transit... time.

This may also be due to using a strain of blackberry that withstands transport better -- a trait which, in produce, often goes with a lower nutritional profile.

If fruit is dried correctly (a big "if"), then it retains much of its nutritional value and has the considerable advantage of concentrating it into a smaller quantity. Thus, the 100gm of dried, possibly higher-quality berries turned out to have the biggest antioxidant kick -- by a factor of roughly 10 over frozen berries.



Subjective matters

I've been thinking about this article since I read it a month ago.

Then, as I was struggling with brain fog this weekend, I got a pair of half-pints of organic raspberries from a large commercial producer which is famous for consistently mild, sweet-smelling berries that hold their shape despite being shipped all over. They were on sale.

I ate a whole package, hoping for that antioxidant kick that would chase some of the fog away. Not wanting too much sugar in my system (and hating to spend that much money in one sitting), I hesitated before starting on the second package, but no good. I might as well have been eating cardboard for all the good it did. I began to wonder if I should bother with raspberries at all, given how every bite I eat has to matter.

The next day, I stopped at a roadside stand and picked up a single half-pint of organic raspberries from a farmstand, for slightly more than the brand-name berries cost on sale, but less than they cost otherwise. (Farmstands are generally worth the gas I spend on finding and mapping them.) They were much smaller, much darker, and some of them were squashed. They wound up spilling in the car, and I pulled over to scoop them up and keep them from messing up the rest of my shopping. I quickly gave up on extracting them neatly, and just shoved the spilled half into my mouth.

Quite apart from the flavor explosion -- which was an eye-opener in itself -- within a minute, the fog had lifted. My eyes were sharper and my head was clearer than it had been in awhile. THAT was the antioxidant kick. It lasted for hours, and I got another one when I ate the second half.


Summary and context

A lot of the fuss over what to eat can be resolved with a little common sense and remembering what you learned in grade school when you were sprouting beans in little cups.

How fresh your food is, probably matters more than exactly what it is.

How well it was grown, probably matters more than the packaging.

And, if you're lucky enough to live near farm country, roadside stands are worth your time.

If not, build farmer's markets into your schedule, because they bring the fresh food right to your neighborhood, with very little time between the soil and you.

I've found that each bite of more nutritious food is more rewarding in every sense, and I wind up needing less to meet my needs. It's economical in the long run, although I remember it took a few months of eating good food voraciously to catch my impoverished system up. That cost a lot up front, but it paid off in the end: my system became more efficient and my tastes evolved for satiation, not overstimulation. I eat enough and am genuinely pleased; that eternal nervous quest for more-more-more is gone.

Grocery stores are for filling in after the farmer's market and roadside stands, in my view. I have a limited budget and stringent nutritional needs, so I've come to that realization the hard way. This study just reinforces my discovery in a different way.

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