Carbohydrates that tend to be disruptive for levels of sugar in the bloodstream (high glycaemic index carbs) can provoke disease-causing changes in the physiology and biochemistry in the body, including enhance inflammation (see here for more about this). The pro-inflammatory effect of high-GI carbs has important implications, because inflammation turns out to be a key underlying process in conditions such as cardiovascular disease (e.g. heart attack and stroke) and cancer.
Cardiovascular disease and cancer are but two conditions that have links with inflammation in the body. Others include infectious diseases (e.g. septicaemia, pneumonia, flu), diabetes, lung disease, gastrointestinal disease (e.g. stomach or duodenal ulceration) and kidney failure. Inflammation can cause debilitating disease and death too. Bearing in mind that high-GI carbs can increase inflammation, could they increase the risk of death from inflammatory conditions aside from cardiovascular disease and cancer?
That is essentially the question posed by a piece of research published this week in the American Journal of Clinical Nutrition [1]. In this study, 1490 postmenopausal women and 1245 men aged 49 or older were followed over a 13-year period. Women eating relatively high-GI diets, compared to those eating relatively low-GI diets, were found to be almost 3 times more likely to die from inflammatory diseases (excluding cardiovascular disease and cancer). This association was not found in men, however. There was no association in either men or women between dietary GI and risk of cardiovascular death either. Previous studies, however, have found that higher-GI diets are associated with a 20-100 per cent increased risk of cardiovascular disease (see here).
Why the association between higher-GI foods and increased risk of death from inflammatory disease in women but not in men? The authors point to previous research which demonstrates stronger links between GI and things like inflammation, excess weight, metabolic syndrome and type 2 diabetes in women than in men. They also point out evidence which showed generally higher ‘antioxidant status’ in men up to the age of 75, which might afford men greater protection against the pro-inflammatory nature of high-GI carbs.
My lasting impression from this study is that it’s perhaps a good idea to keep inflammation in check in the long term. A decent intake of omega-3 fats might be one approach here, but so is eating a diet of relatively low glycaemic index and load. One often-used marker for inflammation in the body is a substance known as ‘C-reactive protein’ or ‘CRP’ for short. The authors of the study discussed here cited evidence linking the consumption of low GI/GL diets with lower CRP levels in healthy overweight individuals [2] as well as in individuals with type 2 diabetes.
References:
1. Buyken AE, et al. Carbohydrate nutrition and inflammatory disease mortality in older adults. Am J Clin Nutr 23 June 2010 [epub ahead of print publication]
2. Pittas AG, et al. A low-glycemic load diet facilitates greater weight loss in overweight adults with high insulin secretion but not in overweight adults with low insulin secretion in the CALERIE Trial. Diabetes Care 2005;28:2939-41
3. Wolever TM, et al. The Canadian Trial of Carbohydrates in Diabetes (CCD), a 1-y controlled trial of low-glycemic-index dietary carbohydrate in type 2 diabetes: no effect on glycated hemoglobin but reduction in C-reactive protein. Am J Clin Nutr 2008;87:114-25
John,
One of the things that gets me with the whole GI/GL thing is that it seems to be increasing used to mask the real foods that fall into the higher and medium categories. That is, when one talks about a high GI diet, does Joe Average Punter know what this means? I suspect that believe that it is the likes of sugar, fizz, and white bread, correctly so. But I also suspect that they think pasta, brown rice, wholegrain bread, and wholegrain cereals are fine.
When you look at the GL at which problems start to occur, it becomes clear that fruits and vegetables are pretty much the best means of keeping to this target.
I blogged on this recently here:
http://primalmuse.blogspot.com/2010/05/would-you-like-some-heart-disease-to-go.html
That s really an interesting study about low GI carbs and wt control in men and women -im a wt management specialist and ive tried to use that theory w high insulin and high crp and low GI diets was much better and yielded better outcomes for wt and health parameters including HBA1c and crp
John, why do men generally have a higher ‘antioxidant status’ than women? Can you give an example of inflammatory disease which excludes cardiovascular disease and cancer?
GI / GL is a useful but limited dietary tool. We don’t eat single foods, but foods with different GI / GL ratings in combination. Some fruit with a high GI may be good in moderation because of the vitamins, phytochemicals, antioxidants and fibre they contain.
A nutritionally rich and varied diet should be the goal. Because carbohydrates have anti-nutrients (phytates in grains, oxalic acid in some vegetables, purines etc) it is probably good not to over-consume them. Adequate protein and plenty of natural dietary fat is beneficial.
I suspect that over-consumption of pro-inflammatory Omega 6 vegetable oils is a contributory factor to poor health status. It is probably how we use them too, for purposes they are not well suited, ie high heat frying. Having done some reading on dietary fats I have tossed my supermarket bought Canola oil and rice bran oil. I use virgin cold-pressed olive oil for cold use. For cooking I use coconut oil, lard, bacon fat, duck fat, tallow and butter.
Inflammation appears at the root of many serious healthy issues. Recently I read about the role of serrapeptase — the way I understand it, this enzyme “eats” digests non-living tissue when used properly. In this way, serrapeptase (initially from silkworms, now made by fermentation) has an ability to eliminate the build up of tissue causing the inflammation. I like to see cover this topic. Thanks.
In my point of view the abundance of Reactive Oxygen Species and Advanced Glycation Endproducts that come into existence with the metabolism of sugars (especially fructose) form the culprit. Furthermore I think it is not the shortage of omega 3, but the overload of omega 6 that stimulates inflammation.
I’m sorry Jamie, but it goes against the grain (yep), all my instincts learned and handed down through generations – which I believe is getting lost now as we talk simply about macronutrients of food as being protein, carbs and fats and not what generations of people found healthful to eat before science came along to tell us what to eat – and as we see here with the demonization of saturated fat – not always successfully. But if you are saying that indigenous grains used for generations are as bad for us as fizz pop, sugar and white flour – I just don’t get it. First – when making a meal, they are not eaten in isolation and I thought there was some thinking that eating a food that registered high on the GI/GL like brown rice, when eaten with protein would not spike blood sugar so much? Appreciate it if anyone has thoughts on this? So – If I take what is considered a culture that before typical ‘Western diet’ influence’ infiltrated the cuisine, like Japan and cooked traditionally, I would use for spices: ginger, miso paste, turmeric, bonito flakes and rice vinegar with produce such as shitake mushrooms, dried seaweed (kombu, duise) Asian mustard cabbage, scallions or chives, spinach and/or bean sprouts with buckwheat or whole-wheat noodles or short grain brown rice and organic free-range sustainably farmed pork spare ribs, pork shoulder or tofu or fish (trout or sardines). I totally agree lots and lots of veggies and sustainably raised meat or sustainably caught fish – however noodles or rice are integral to this dish not least because I would rather eat a little less meat that is more expensive because it is sustainable and organic than lots more meat that is cheaper simply because that animal has been raised in a totally unnatural way (changing it’s fatty acid profile being one consequence of this)
Traditional cooking in many cultures would have used indigenous grains such as amaranth, barley, brown rice, corn grits, couscous, kasha, oats, spelt, triticale, bulgur wheat and wild rice along with certain pulses, chickpeas etc in casseroles and stews with lots of veggies to make the meat or fish go further – this being the most expensive component of the meal and often hard to afford.
It’s not really correct to say that Asian cultures base their diet on rice. They do eat rice, yes, white rice but not as much as we think. Of course it depends on resources/poverty, tradition. Check Stephan’s post on rice for more information.
http://wholehealthsource.blogspot.com/2010/06/in-search-of-traditional-asian-diets.html
Brown rice contains a lot of phytic acid and traditionally the bran was always removed partially or totally.
Just because grains were used traditionally, exactly for the reason you mention, which is to make the meat go further or to replace it, when needed, it doesn’t mean they’re an optimal food. They need to be prepared carefully, like pulses, and nowadays, many people don’t have the skills or the time to do it. They are some grains that are better than others, overly modified wheat is not one of them.
See dr. Davis interesting posts on emmer and eincorn.
http://heartscanblog.blogspot.com/2010/06/in-search-of-wheat-emmer.html
The idea that eating whole grain pasta, brown rice or whole grain bread is better for you is wrong. Adding bran is not healthy (indigestible fiber, irritating the gut, contains phytic acid that binds to minerals in the food), pasta still spikes your BG 4 hours later and the breads’ GI are very close irrespective of the fact that it contains a bit of bran or not.
As dr. Briffa previously mentioned, the GL of the meal is more important. To be on the safe side, we end up eating meat, dairy products and veg, with a few potatoes and a bit of white rice thrown in for ‘variety’ or for saving money.
Thank you for directing me to Stephan’s post which is really interesting and I would agree with all that he says there. He seems to sum up by saying
“The diet most likely resembled that of non-industrial Africans – an assortment of traditionally prepared grains, root veg, legumes, vegetables and a little meat”.
The consumption of white rice, it would appear, just like for Western countries and white bread, was an attempt to copy the ways of the wealthy. He says that “In Akira Kurosawa’s movie ‘Seven Samurai’ ….. peasants ate home-processed millet and barley, while the wealthy ate white rice.”
I totally agree that the GL of a meal is important – but I am not totally convinced that say having for my breakfast (being from good Scottish stock) porridge made with unadulterated oats cooked with unsulphured currents to give a little sweetness and served with fruits in season (at the moment – blueberried – yay) almonds or pumpkins seeds and or walnuts and some sheep’s milk yogurt is in the same camp as eating cornflakes, homogenised, pasturised cow’s milk and added sugar.