June
2008
Reader Response: Insulin Index
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Oh, Pancreas. You’re so silly…
Reader Pete asked for some thoughts on the “Insulin Index,” a measurement chart similar to the glycemic index. While the glycemic index calculates the relative blood sugar rise induced by given foods, the insulin index evaluates the insulin response generated by 38 different foods.
The insulin index, which first made its appearance in a 1997 American Journal of Clinical Nutrition article, was primarily the creation of Susanne Holt, a graduate student at the time and now a doctor. Interestingly, Holt, her supervisory co-authors, or other researchers haven’t chosen to conduct further research to update the “preliminary” results of their insulin index study since its creation eleven years ago now.
While Holt and her co-authors found a high correlation between glycemic index and insulin index measurements, they stumbled upon an intriguing exception. High protein, virtually no-carb foods like meat and eggs, while low on the glycemic index, measured high on the insulin index. In other words, while the meat and eggs didn’t cause a spike in blood sugar the way most carbohydrates do, they did result in an unexpectedly significant rise in insulin. (Baked goods, with their high levels of refined carbs, elicited a very high rise in insulin as well. Of course, this comes as less of a surprise.)
Obviously, the index has some eyebrow-raising potential, especially in those of us who choose a high protein diet. But there’s more to the story here. First off, let’s remember that the protein-rich foods didn’t result in the physical stress of blood sugar spikes. But what about that rise in insulin? Why? Should I be concerned about that omelet I ate for breakfast?
Insulin, in and of itself, is a good and necessary thing. It promotes the storage of nutrients after all. In our natural, primal state, this was an essential process. Even in our modern lives, this storage process is still vital. (We just have a nasty habit of flooding the system these days.) In the case of high protein foods, it makes perfect sense that the body recognizes the need to store amino acids. (Primal life wasn’t a perfect set schedule of three square meals a day after all.)
The insulin helps drive amino acids into the muscle cells where they’re needed. At the heart of this process, one thing is for certain: the body knows what it’s doing.
But there’s another dimension to the protein-insulin issue. When we eat protein-rich food, another chemical is released by the body that actually has a contrary effect to insulin. Protein-rich foods also result in a release of glucagon. (Carb-rich food does not.) Glucagon raises blood sugar levels in part to allow for absorption of amino acids in the liver and their subsequent transformation there to glucose. In our evolution, we developed the capacity to make what we required out of what was available. If dinner was going to be part of a mammoth carcass, then the body could enjoy the protein it needed and use insulin response to store essential amino acids. Simultaneously, it had the glucagon to keep blood sugar stable in the absence of carb-based foods.
What does this tell us? It underscores the fact that we don’t need to (and shouldn’t) include extra carbohydrates in our diet. The carbs we get from vegetables and the glucose that can be made even from protein-based foods offer plenty of the right fuels our bodies need.
For people without diabetes, the insulin and glucagon responses mitigate each other, and we’re looking at a healthy picture. For people with diabetes or impaired insulin response, however, this picture is much different. In diabetics, this crucial equilibrium is damaged. The body not only has difficulty compensating for blood sugar spikes from carb intake, it’s also at a disadvantage when it comes to low-carb, protein-based meals with the lack of insulin-glucagon balance. (Another reason to avoid developing diabetes from the outset.) Nonetheless, diabetics fare better with a low-carb diet.
In short, while the insulin index raises some intriguing points, I don’t think it undermines the Primal Blueprint or unravels existence as we know it. It’s another bit of research that illuminates the natural interaction of our body’s systems with the diet we feed it. The index highlights the need for responsible food choices based on our inherent physiological functioning.
Now, pass the bacon.
Thoughts? Comments? Insights?
Mr. Gunn Flickr Photo (CC)
Further Reading:
The Importance of Blood Sugar Level
The Definitive Guide to Grains
The Definitive Guide to Insulin, Blood Sugar and Type 2 Diabetes (and You’ll Understand It)
so wouldnt this mean that when u eat a high protein high fat meal, that the fat will get stored due to high insulin? if fat + carbs results in a synergistic insulin response, might fat and protein result in the same thing?
What I would really like to find out is whether eating fat really corresponds into storage as fat.
From what I gather - eating protein and fat help to repair the body as the body is essentially made up as amino acids and fatty acids.
Carbs (glycogen) is actually used by the body as fuel. So, if you eat excess carbs, then you store it as fat. But apparently if you eat fat, unless you eat more than your caloric expenditure, you don’t store it as fat, because fat is used by the body for structural and repair reasons…
I wish someone would explain once and for all what happens to fat when you eat it!
If protein creates a large insulin response, it gets kind of complicated to understand how to maximize the natural release of growth hormone. Exercise (especially anaerobic exercise) stimulates an extra release of growth hormone. I am among many exercisers who try to eat some protein right after exercising to take advantage of a “window of opportunity” to replenish muscles and to minimize muscle soreness; and some research has shown that eating protein stimulates an extra release of growth hormone. Insulin supposedly dampens the release of growth hormone so many people advise against eating carbs right after exercising. I plan to continue to eat unflavored whey protein after exercising, but this news make me wonder.
Kady and Arthur,
Interestingly, we know that higher fat mitigates the insulin response, so a high fat/high protein meal will likely elicit a lower insulin response than just high protein. It was the “trimmed beef” tested alone and the almost-non-fat fish that had the relatively higher insulin responses among the high protein groups. I think this all falls in line with the Primal Blueprint.
Does whey protein isolate powder, one without any carbs, cause an insulin spike? If so, does the rise in blood sugar give way to any excess protein consumed being converted to fat for storage? Thanks for the help.
Marc,
The people who did the insulin index only tried it on a few foods. Whey powder wasn’t one, so we don’t know if it causes a spike. If it did, it probably wouldn’t by itself promote fat storage.
Mark-
Belated thanks for this post. Interesting stuff. It looks like acute insulin spikes are probably not as detrimental as chronic ones, and happen for different reasons.
Researchers tell us that milk is insulinogenic. That is, it causes an insulin spike that cannot be explained merely by its concentration of carbs. Some people attribute this to the whey protein. But what does this all this mean for health? Is this good or bad? I have heard that it can be helpful for diabetics to prevent blood sugar spikes. What about everybody else? And what if you drink milk without any additional carbs, wouldn’t that theoretically cause short-term low blood sugar? And finally, I’m curious to find out how milk compares with milk-derived products, like cottage cheese (which I love) and yoghurt. Cottage cheese, for example, has almost no carbs (especially lactose), but I assume it still has whey protein.
Jimmmy:
There are many explations for the insulinogenic nature of milk. Here are some ideas for you:
1) Lactose is converted to galactose (a blood sugar similar to glucose) which causes insulin spikes just like glucose.
2) Protein also causes a lesser insulin response so the whey protein is certainly a contributing factor. Casein protein (also found in milk) causes a very low response because it takes a long time to digest. I remember reading that casein protein doesn’t always digest fully and might even cause health problems because of this.
Other things to think about when it comes to milk are:
The chemicals/hormones injected into most cattle to increase size and production of milk (specifically Insulin-like Growth Factor I (IgF-I) which is used by scientists to grow cancer cells, and an abundance in the body is not a good thing.) For more on these see: http://www.notmilk.com and/or google: Milk - The Deadly Poison by Robert Cohen.
Plus, cow milk is for calves, nature never meant it for human consumption so if you want to be strict Paleo/Primal then limiting intake might be a good idea.
To answer your question about blood sugar spikes and health. The short answer is: yes, it does matter (if your goal is health and longevity) to minimise insulin spikes. The long (very long) answer can be found here: http://drbass.com/rosedale2.html it’s a great article!
Hope that all helps!!! I’m currently researching the hormonal systems etc. of metabolism so it might not be perferct but at least it’s fresh in my mind!
Russ
Russ, great reply to Jimmy’s question. My jury is still out on dairy.