LE Magazine May 2003
Eating Food Cooked At High
Temperature Accelerates Aging
A new study published in the Proceedings of the National Academy of Sciences1 reveals that eating foods cooked at high temperature may increase the rate at which we age. According to this study, the ingestion of high temperature cooked foods causes chronic inflammation and the formation of advanced glycation end products.
Life Extension members have been frequently warned about the dangers of chronic inflammation and glycation. For the benefit of new members, I will succinctly explain these two lethal processes.
As humans age, there is a systemic increase in inflammatory cytokines (destructive cell-signaling chemicals) that contribute to many degenerative diseases. Rheumatoid arthritis is a classic disorder where excess levels of cytokines cause or contribute to the destructive inflammatory syndrome. While inflammatory cytokines can cause agonizing pain, they also disrupt the linings of our arteries, mutate DNA and degrade brain cells. Chronic inflammation is directly involved in diseases as diverse as cancer, atherosclerosis, diabetes, aortic valve stenosis, congestive heart failure, Alzheimer's disease and kidney impairment.
In aging people with multiple degenerative diseases, we often find elevated blood levels of C-reactive protein, indicating the presence of an inflammatory disorder. When a cytokine blood profile is conducted in these individuals, we usually discover excess levels of one or more of the pro-inflammatory cytokines. The most common pro-inflammatory cytokines are tumor necrosis factor-alpha, interleukin-6, interleukin-1(b) and/or interleukin-8.
Chronic inflammation inflicts devastating effects, especially as humans grow older. The lethal consequences of inflammation are clearly established in the medical literature.2-14 The good news is that many of the nutrients, hormones and drugs being taken by Life Extension members suppress the production of these deadly inflammatory cytokines. As you will soon read, avoiding foods cooked at very high temperatures can also reduce production of inflammatory cytokines.
How glycation cooks us to death
The glycation process that turns a chicken brown in the oven is exactly what happens to the proteins in our body as we age. When body proteins react with sugars they turn brown and fluorescent, lose elasticity and cross-link to form insoluble masses that generate free radicals. The resulting advanced glycation end products (glycotoxins) accumulate in our collagen and skin, cornea, brain and nervous system, arteries and vital organs as we age. Unfortunately, glycotoxins are highly resistant to the normal processes of protein turnover and renewal that maintain the healthy tone of youthful body tissues and organs.
How does the body cope with these chronic assaults on proteins? Long-lived cells, such as neurons and muscle cells, contain high levels of a dipeptide called carnosine, made up of histidine and beta-alanine. Unlike ordinary antioxidants, carnosine blocks numerous pathways involved in the glycation process.
Age-accelerating effects of glycation
The other pathological aging mechanism exacerbated by eating high temperature cooked food is the formation of advanced glycation end products (A.G.E.'s). Glycation can be described as the binding of a protein molecule to a glucose molecule resulting in the formation of damaged protein structures. Many age-related diseases such as arterial stiffening, cataract and neurological impairment are at least partially attributable to glycation. These destructive glycation reactions render proteins in the body crosslinked and barely functional. As these degraded proteins accumulate, they cause cells to emit signals that induce the production of inflammatory cytokines.
The glycation process is presently irreversible, though a recent study indicates a drug in clinical trials may be partially effective. Life Extension members take supplements to help protect against glycation. According to the Proceedings of the National Academy of Sciences study, consuming foods cooked at high temperature accelerates the glycation process, and the subsequent formation of A.G.E.'s.
Medical establishment finally recognizes importance of C-reactive protein testing
The Life Extension Foundation long ago advised members to have an annual C-reactive protein blood test to detect systemic inflammation that could increase the risk of heart attack, stroke, cancer and a host of age-related diseases. In fact, the C-reactive protein blood test has long been included in the Male and Female Panels that are ordered annually by many Foundation members.
On January 28, 2003, the American Heart Association and Centers for Disease Control & Prevention (CDC) jointly endorsed the C-reactive protein test to screen for coronary-artery inflammation to identify those at risk for heart attack.
The value of the C-reactive protein test was evident to the Life Extension Foundation many years ago. Millions of Americans needlessly suffered crippling strokes, sudden death heart attacks and other diseases that could have been prevented if the medical establishment had utlized the C-reactive protein blood test sooner.
A more succinct descriptive term for "advanced glycation end products" is "glycotoxin", since "advanced glycation end products" are toxic to the body. We will use the word "glycotoxin" from here on to describe the term "advanced glycation end products".
Cooking and aging have similar biological properties
Cooking foods at high temperatures results in a "browning" effect, where sugars and certain oxidized fats react with proteins to form glycotoxins in the food. Normal aging can also be regarded as a slow cooking process, since these same glycotoxins form in the skin, arteries, eye lenses, joints, cartilage, etc. of our body.
The Proceedings of the National Academy of Sciences study shows that consuming foods high in glycotoxins might be responsible for the induction of a low-grade, but chronic state of inflammation. In addition, the glycotoxins in food cooked at high temperatures also promote the formation of glycotoxins in our living tissues. The implication of these findings is profound.
Feeding foods rich in glycotoxins to diabetics
The presence of glycotoxins in the blood of individuals with diabetes has been known for quite some time.15 To ascertain reasons for this, a group of diabetics were studied to assess the difference between consuming a diet high in glycotoxins compared to diet low in glycotoxins. The high glycotoxin diet was induced by heating food for a longer period at higher temperatures compared to the lower glycotoxin diet. Using a variety of foods, the scientists were able to increase the glycotoxin content five-fold by cooking the food at high temperatures.
After only two weeks, diabetics on the high glycotoxin diet showed a 50% to 100% increase of glycotoxins in their blood and urine compared to the group consuming the low glycotoxin diet. The group eating the high glycotoxin food also showed increased levels of inflammatory blood markers such C-reactive protein and pro-inflammatory cytokines such as tumor necrosis factor alpha.
In order to determine whether these significant changes were merely an acute response to an altered diet, the scientists carried out a second study that lasted for six weeks. Again, those consuming a diet high in glycotoxins had higher concentrations of glycotoxins in their bodies, along with increased inflammatory cytokines in their blood.
Small changes in cooking methods and diet can slow aging
Researchers at the Department of Geriatrics, Mount Sinai School of Medicine have determined that A.G.E.'s or glycotoxins are found in foods that are overheated or cooked at very high temperatures. This includes foods that have been fried, barbecued, broiled or cooked in the microwave. While the worst culprits are animal products, since they contain a higher amount of "bad" fats that speed up the formation of glycotoxins, any food that is exposed to extreme high heat can scorch the natural sugars in food and create glycotoxins. This also true of many pre-packed foods that have been preserved, pasteurized, homogenized or refined, such as white flour, cake mixes, dried milk, dried eggs, dairy products including pasteurized milk, and canned or frozen pre-cooked meals.
While it may be impossible to totally avoid gycotoxins, it is possible to reduce exposure by changing the way food is prepared. Consider steaming, boiling, poaching, stewing, stir-frying or using a slow cooker. These methods not only cook foods with a lower amount of heat, they create more moisture during the cooking process. According to Dr. Helen Vlassara*, the study's lead researcher, water or moisture can help delay the reactions that lead to glycotoxins. Marinating foods in olive oil, cider vinegar, garlic, mustard, lemon juice and dry wines can also help. Finally, consider making small diet changes by adding more fresh fruits and raw and steamed vegetables to your diet.
* Vlassara H et al. Inflammatory mediators are induced by dietary glycotoxins, a major risk factor for diabetic angiopathy. Proc Natl Acad Sci U S A 2002 Nov 26;99(24):15596-601.
The researchers also found that eating diets low in glycotoxins reduced the level of other potentially harmful substances in the blood, including LDL cholesterol ("bad cholesterol"). During the two-week, low-glycotoxin diet, diabetics had lower LDL levels than those on a high-glycotoxin diet. A six-week, low-glycotoxin diet caused a 33% reduction of LDL, while a high-glycotoxin diet increased LDL by 32%.
Aging control and weight loss
This study on human diabetics raises intriguing possibilities of preventing disease and slowing aging via proper food preparation. First of all, previous studies have shown that caloric restriction prolongs life span in rodents while simultaneously decreasing glycotoxin formation in body tissues.16 There is now considerable evidence that the same glycotoxin formation that occurs during cooking also occurs inside the body during normal aging17 and at an accelerated rate in diabetics.18 For example, glycotoxins accumulate faster in the skin collagen of diabetics compared to non-diabetics.19 We also know that glycotoxins engage cell receptors in such as way as to promote tumor growth and metastasis (via mechanisms that stimulate cell migration, tumor cell growth factors and enzymes that digest the extracellular matrix).20
While this study on human diabetics is preliminary and needs confirmatory results in healthy populations, there were other benefits associated with consuming a low glycotoxin diet. Not only did the diabetics consuming the low glycotoxin diet lose weight, but their blood glucose levels also dropped. In the group eating the high glycotoxin diet, blood glucose levels increased. Elevated glucose levels can trigger production of deadly inflammatory cytokines.
It should be noted that the number of calories, carbohydrates, proteins and fat was the same in both the high and low glycotoxin diets. The diabetics consuming the low glycotoxin diet, however, lost weight. It is well known that reducing excess weight and glucose levels confers longer life.
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