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Diet affects cellular aging in the longer term
Each time the chromosome divides to create new cells, the telomeres get shorter and shorter until the chromosome breaks down and the cell dies. This is known as "programmed cell death," a normal process that can, however, be set off prematurely. That premature cell death has been linked to inflammatory states such as cancer, heart disease, and high blood pressure.
Live longer (on a cellular level) with a Mediterranean Diet
... making use of data gathered through the Nurses' Health Study (a large-scale, long-term research study), scientists at Harvard assigned Mediterranean Diet scores to the dietary questionnaires of over 4,600 participating women who were considered "healthy controls:" they were free of chronic diseases such as cancer or heart disease. These women had also provided blood samples which had previously been used to measure telomere length
Omega-3 Fatty Acids May Prevent Cellular Aging
While it is natural and normal for cells to die, which is known as "programmed cell death," emerging research posits that the number of telomeres present on certain cells is linked to biological aging, which is different from chronological age in that these telomeres are also affected by genetic and environmental factors.
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I've written in numerous Health & Nutrition Bites about telomeres, the DNA sequences that are considered markers of cellular aging (read a broader explanation of their function). In these Bites we've seen research that indicates that a Western diet is associated with premature cellular aging (as measured by telomere length), while those following a more Mediterranean-style diet overall seem to have longer telomeres.
Other research has sought to tease out which foods, specifically, affect telomere length. Omega-3 fatty acids have been identified as one possible factor linked to longer telomeres, while a study in Korea found that red meat, both processed and unprocessed, along with sweetened carbonated beverages, were linked with shorter telomeres. Recently a study published in the Journal of Nutrition looked more closely at telomere length in relation to red meat. (J Nutr 2016;146:2013-8)
The authors in this study utilized data gathered from an ongoing study of over 2,800 Native American Indian individuals from 94 families in Arizona, North and South Dakota, and Oklahoma. This study, the Strong Heart Family Study, was created to identify genetic factors affecting the risk of cardiovascular disease in Native American Indians. At the start of the study, between 2001 and 2003, the participants provided blood samples, were interviewed regarding demographic and lifestyle factors, received a physical exam, and responded to a standardized Food Frequency Questionnaire that included foods their communities commonly consumed, from menudo and pozole to guysava (roasted corn, beef, and chili), fry bread, and canned meats.
As other studies have done, the researchers standardized the participants' intake of unprocessed red meats (ribs, burgers, deer, liver, roast beef, etc.) by designating a serving to be 100 grams (about 3.5 ounces), while a serving of processed meats (including canned meats, breakfast sausage, luncheon/deli meats, and hotdogs) was considered to be 50 grams (about 1.7 ounces). The number of servings of red and processed meats were then correlated with the telomere length of each participant.
After adjusting for variables like age, Body Mass Index, gender, cholesterol scores, and blood pressure, the authors found that although unprocessed red meat appeared to have no effect on telomere length, consuming processed red meats did: each additional serving of processed red meats was associated with a shorter telomere length equivalent to being 4 years older. You might say that eating sausage, hot dogs, and canned meats ages you on a cellular level.
There are two caveats for this study: first, this is a cross-sectional study, which looks at a single moment in time. While we can say that there is an association between processed meat consumption and telomere length, we can't say with scientific certainty that one caused the other. Further, the authors note that those participants with less education ate more processed red meat than those with more education: "...education may be a marker of social disadvantage, and a handful of studies have shown a positive relation between social disadvantage and telomere attrition." Consuming more processed red meat may also be a marker of social disadvantage, meaning that the true culprit might be social disadvantage in general and not red meat specifically.
On the other hand, other research links processed meat intake with higher levels of inflammation, which we know promotes the cell turnover that shortens telomeres. Your take-home should continue to be minimizing processed meat intake and choosing nitrate-free processed meats whenever you can.
First posted: January 11, 2017