Wednesday, November 11, 2009

The Raw and The Cooked of Enzyme Supplementation

Where's the beef on enzyme supplementation? Our pancrease creates gagillions of digestive enzymes; our guts are full of happy bacteria by the gigaorificzillions. So why do we need to add the expense of additional stuff? I admit i have a hard time with the push for enzyme supplementation. But what's the science?

Maybe maybe maybe in the case of a specific inflammation or digestion issue there may be grounds for proteolytic enzyme supplementation. But as a general rule? Likewise the argument that we need such supplementation because we eat cooked food and that destroys food enzymes making it difficult to get nutrients from the food? Surely there's good science to show the opposite is true?

So in such a state of quandry, who'm i gonna call? Why, RD and PhD candidate Georgie Fear of We looked at some common claims around enzymes, and Georgie put together the following points.

1. The common division [often seen on the web] of enzymes into "digestive", "food", and "metabolic" enzymes is arbitrary. Many of them do the same things. Proteolytic enzymes from papaya, for example (which you'd call a "food" enzyme), function in the same manner as proteolytic enzymes pepsin produced in the stomach. They all cleave peptide bonds. Similarly, collagenases (completely unrelated to digestion) are present in joints and other sites throughout the body. They also cleave peptide bonds to remodel cartilage and connective tissue, etc. So classify enzymes based on the source if you like, but it is only a simplification. This has no utility in actual science however, where enzymes are commonly classified by chemical process (example) or mechanism.

2. Claims that Cooked foods containing NO enzymes is a similar oversimplification, not that it matters, as I'll point out in #3. Cooking is a spectrum of exposure to various degrees of heat for various lengths of time. Enzymes vary in their heat stability, resistance to denaturation by acid, etc. To do RNA replication in the lab we use a polymerase from organisms that thrive near thermal vents (T. aquaticus), precisely because it won't be denatured even after many many cycles of heating and cooling. I'm not going to bother looking up individual food enzymes and their denaturation points, but suffice to say a blanched vegetable (cooked for 1 min) is different than one broiled for an hour. I'm sure different foods, cooked for different amounts of time and different temperatures, would contain varying amounts of enzyme activity.

(Why can't you use canned pineapple to make jello? Because it has natural protease activity. Hmm, survived the canning process didnt it?)

But I'm going to get to why it doesn't matter.

3. Why doesn't it matter that cooking supposedly decreases enzymes in food? Because you don't need any enzymes from food. It wouldn't matter if you intentionally destroyed every enzyme from every morsel you ate. Your body is wonderfully designed to efficiently digest and assimilate any and all digestibles you give it with its own enzymes. There are a multitude of enzymes used in the gut, starting with ptyalin right in your saliva which starts working as soon as you bite. The stomach provides acid and more enzymes (which are activated by the acid environment.) Upon proceeding to the small intestine, bicarbonate ions neutralize the stomach acid and activate yet another set of enzymes supplied by the pancreas, which function best at the higher pH. Further enzymes are produced by the small intestine itself. You have quite an array, you dont need any enzymes from your meals.

4. Food enzymes may not have any in vivo activity. Take papain from papaya for example, which some people think will help them digest protein. Optimal ph for papain activity is 6.0-7.0. Neutral. Not what you'd find in the stomach. Your own protein digestion is optimized work in that acid environment, and then continue at ph8.0 in the small intestine. I don't know if most plant enzymes will still be active after getting dumped in to the acid environment of the human stomach, but I'd guess that most would be denatured by the acid.

5 So-called Enzyme Limitation: in a proponent's paraphrase of Edward Howell's Enzyme Nutrition:
We have a limited enzyme potential. In other words, we do not manufacture an unlimited supply of enzymes. The more our body is required to make food enzymes, the less it makes metabolic enzymes.
Well that would likely fall under the "Completely wrong" category.
You also will not run out of heartbeats and die early if you exercise. This is based on the fact that enzymes are not themselves changed in their reactions, but can catalyze millions of reactions. Second, enzyme synthesis, activation, and kinetic activity are regulated. Enzyme production can be increased or decreased at the synthesis step. Many enzymes are also synthesized as zymogens, which need cleavage before becoming active. This also is a step for up- or down- regulation. Natural inhibitors or activators can further fine tune activity, you make both. Natural inhibitors keep enzymes from running rampant in the body, and coactivators/coenzymes also help keep enzymatic activity in check.

(Scroll to The Catalytic Activities on Enzymes are Regulated)

As for the second sentence, that's what polite company might call "complete garbage." Read about gene expression here for example

6. Supposed Enzyme Inhibitors action of raw seeds, etc
Another claim from Enzyme Nutrition proponents: "Raw grains, nuts, seeds, and beans contain enzyme-inhibitors. If they are germinated or properly soaked, the enzyme-inhibitors are neutralized."
Again, alas, wrong based on what we know in the science. Sprouting grains does cause dramatic changes in enzyme concentration and inhibitor activity, (in my experiments I carefully sprouted peas to isolate glucosidase, which is many times higher than before sprouting them). However, most enzyme inhibitors are not neutralized or destroyed by soaking. This is the reason why some foods are not safe to eat without full cooking (yes, boiling. Until cooked.) Soybeans for example contain many protease inhibitors, which will not be altered by a soak. Many other legumes and beans also shouldn't be eaten raw, because the enzyme inhibitors will make digestion difficult.

Granted, consuming raw beans would make for digestive trouble, but not all enzyme inhibition is bad. Alpha-glucosidase inhibitors (which are isolated from white kidney beans) are helpful to slow down carbohydrate digestion, which assists diabetics in managing blood glucose. Many protease inhibitors have medicinal uses for disease states.

Here's a well-cited article published in 2007 on deriving medicinal protease inhibitors from plants (note the author -mc).

7. Raw food isn't more easily absorbed or digested than cooked. In contrast, cooking makes many nutrients far more bioavailable. Carotenes and lycopene for example. If there is any item which we aren't capable of digesting, it's cellulose, since humans lack the enzyme to cleave beta linkages. Thus, carbohydrates with these linkages go undigested and we call it fiber.

My last point is that enzymes may be helpful for people with certain medical conditions, but none of these are "food enzymes". T Primarily - lactose intolerance (which occurs when your body doesn't make enough lactose) can be treated by taking exogenous lactase. People with cystic fibrosis or pancreatic diseases often benefit from taking supplemental digestive enzymes, but these also are not found in plants. Human (or bioidentical) enzymes do the job best. That's why we take extra human enzymes when disease restricts the production of our own. Its not a matter of eating more raw plants.

Evolution has created the human body with a well-organized and efficient set of enzymes to digest food as well as control myriad other processes.

It's important to consider the source of information proponents are quoting to back up their assertions about enzymes. Belief in the need to take in exogenous enzymes from food is evidence of someone who seems to be not best aware of recent biology. For reference, the popular reference that many proponents cite for backup, Enzyme Nutrition, was written by a person born in 1898 and published in the 1980s. A lot of research has happened since then in understanding food and enzymes.

Georgie Fear RD

Thank you Georgie!

By all means, please visit Georgie's site - often.

She has a new cookbook i'll be reviewing soon, and as a preview: if you want to eat well but don't feel like a suave chef in the kitchen, but you have a knife and a nuker - check out the cook book called Dig In. Served with smarts and love.


Christian said...

wow! this post is so informative! i was just walking through different blogs here, reading different info and I am glad I've found your page!
All the best!

Bryce said...

Definitely a great post MC. Thanks for all the info. I tend to bring a good dose of skepticism to the latest trendy additions we need to be making to our diets.

One big one would be probiotics. I have seen convincing evidence that fermented foods have beneficial effects for us, but the idea that we need extra bacteria to get the job done seems a bit like a marketing gimmick (so long as we aren't messing with our natural bacteria by eating lots of garbage, grains, sugars, etc).

Definitely enjoying your blog!



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