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Comment by fintechie | Hacker News Reader

> "if you put some berries in a blender and drink it, you're getting entirely different nutrition from eating the berries raw!" That second one is a bit of a strawman, but it shows how absurd claims that crushing or grinding foods ruins the nutrition sound.

Well, for many foods this is 100% true. For instance, it's not the same eating raw garlic, than freshly smashed garlic (<10mins), than garlic smashed 20 minutes ago... because allicin (main active compound of garlic) is unstable and quickly degrades into another compounds...

https://en.wikipedia.org/wiki/Allicin

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Yeah, I was gonna say-- pureeing berries severely impacts dietary fiber, which in turn impacts glycemic index, since your body no longer has to work around nearly as much cellulose to get to the sugar. It's a physical process that has an impact on a chemical process. And of course you chew your food, but you can't chew anything nearly so fine as your blender does.

Here's a more concrete analogy-- sawdust is highly flammable. Many times more so than regular old wood. Why? Better oxygenation, higher surface area, lower per-unit thermal mass (which means less energy required to get a particular chip of wood to its combustion point).

> Yeah, I was gonna say-- pureeing berries severely impacts dietary fiber, which in turn impacts glycemic index, since your body no longer has to work around nearly as much cellulose to get to the sugar.

When I first got my Vitamix, I did some cursory web "research" which seemed to imply that blending made no substantive difference in nutritional value of fruits. Do you have a citation for this conclusion?

The general rule of thumb is cooked digests easier than raw, blended easier than cooked, juiced easiest of all. Think of it as automating preexisting parts of the natural digestive cycle-- you chew your food physically for a reason, obviously, starting in the mouth and continuing in the stomach. Cooking denatures protein. Pureeing similarly breaks down dietary fiber into smaller, more digestable chunks. Everything is still there (excepting volatile organic compounds that degrade once exposed to air, etc), it's a physical process, not chemical. But physical transformations have indisputable effects on chemical reactions. That's not controversial.

(Caveat: nutritional science is very much in the wild wild west days. It's a jungle out there, even in peer-reviewed research.)

https://www.ncbi.nlm.nih.gov/pubmed/3046297

He doesn't have a citation because he's wrong.

But I do, sunshine. Do you?

Your citation is about starch. A better citation in support of your assertion https://www.ncbi.nlm.nih.gov/pubmed/71495

But does that change the nutritional value of garlic (as opposed to changing just the taste)?

If you lose allicin you lose some nice properties (antimicrobial, antiinflammatory, etc):

https://www.ncbi.nlm.nih.gov/pubmed/10594976

But those properties may not be relevant to you when consuming garlic anyway. The vast majority of such studies are showing the properties in isolation (petri-dish).

People love to extrapolate that to "garlic prevents colds", but it doesn't follow. I'm not going to pay to read the full article in this case but you at least have to be careful about this.

> But those properties may not be relevant to you when consuming garlic anyway.

Many of this properties are well known (not so well understood). I posted a random quick example, but there are also studies in vivo (rodent models and humans).

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4103721/

My point was that you have to be careful in general. In the specific case of garlic, I don't draw the conclusion from your second link that it is "well known". There are some promising results for some of the individual diseases, but there are also many caveats. The conclusion states:

"Although it is shown that garlic may have a significant clinical potential either in their own right or as adjuvant therapy in different disorders, however, due to some issues, such as methodological inadequacies, small sample sizes, lack of information regarding dose rationale, variation between efficacy and effectiveness trials, the absence of a placebo comparator, or lack of control groups more standard experiments and researches are needed to confirm the beneficial effect of garlic in various diseases."

> I don't draw the conclusion from your second link that it is "well known".

Then it must be a cultural thing... =) If you read the first sentence in the abstract you can read: "Throughout history, many different cultures have recognized the potential use of garlic for prevention and treatment of different diseases.".

Here in the Mediterranean, garlic is known to be really healthy (along with red wine and olive oil). Many people eat garlic in the morning just for the health benefits, and we even have (famous?) smashed garlic dishes: https://en.wikipedia.org/wiki/Aioli

> My point was that you have to be careful in general.

Agree. Sometimes more context/evidence is required. My point is that the bioavailability of compounds in food might differ if the food is presented in raw or elaborated/processed form.

The first sentence is setting the scene, not confirming the hypothesis. If things being "known" by cultural history was sufficient, we wouldn't need to do science. In reality, a good proportion of "known" things are wrong or the very minimum more subtle than expected.

It is also "known" that being physically cold causes colds (Mediterraneans are especially paranoid about this in my experience). The majority of studies show this to be either untrue or borderline.

I do agree that there is clear potential for chopping food to affect it's nutritional value. I would expect chopping alone to be of minimal impact in most cases if no other evidence was available. Elaborate processing is rather different.

It's almost as though breaking down the cell walls of plant material exposes various molecules to oxygen and other compound in air resulting in the possibility for chemical change than would exist it the material was consumed directly.

Unless you swallow your food whole I imagine that your teeth might break down cell walls too.

Aren't you severely grinding it with your teeth, saliva, and gastric acids anyway?

(Honestly asking, I have no idea.)

Correct. Freshly blended food is also no issue.

The first issue is that you don’t immediately consume it after blending, but wait a few minutes or hours.

The second issue is that the grinding with teeth requires you to spend energy, which reduces the energy you gain from the food.

Right, but teeth are natural and a mortar and pestle are not /s

How does rushing it into an acid bath preserve it?

The goal isn't to preserve it forever, the goal is to preserve it long enough to get to the bacteria which can make use of it.

Antimicrobial food would be bad for you as it would harm digestion.

Not quite true. Antimicrobial doesn't mean quite what you think; it means anti-some-microbes. Honey, for instance, has several antimicrobial or antibiotic aspects. Some honey is so because enzymes in it produce hydrogen peroxide, while other honey is so for different reasons, not fully understood. If you feed mice a lot of honey, their intestinal flora rebalance -- in one study, for instance, feeding mice honey as a food supplement increased their bifidobacteria and lactobacilli counts. This is actually probably good for digestion.

Feed mice a new diet of any kind and their gut will rebalance.

We cannot assume that the environment is innocuous. Our atmosphere is full of nitrogen, oxygen and other chemical compounds able to produce a reaction and modify molecules in any food.

https://en.wikipedia.org/wiki/Active_ingredient

"An active ingredient (AI) is the ingredient in a pharmaceutical drug that is biologically active. " Does it also reduce the amount of rainbows and unicorns? Your own wikipedia link does not say eating garlic is helpful to humans.

Sorry, I meant "active compound"...

> Your own wikipedia link does not say eating garlic is helpful to humans.

As you may know, you shouldn't look in wikipedia for that kind of information... here you go:

"Recent studies support the effects of garlic and its extracts in a wide range of applications. These studies raised the possibility of revival of garlic therapeutic values in different diseases. Different compounds in garlic are thought to reduce the risk for cardiovascular diseases, have anti-tumor and anti-microbial effects, and show benefit on high blood glucose concentration."

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4103721/

But the point here is (in case you missed it): eating smashed food != eating raw food

http://examine.com/supplements/garlic/#summary1-0

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