Daging meningkatkan risiko jantung dan kanker

JAMA http://archinte.jamanetwork.com/issue.aspx?journalid=71&issueid=23009

Red Meat Consumption and Mortality
Results From 2 Prospective Cohort Studies

An Pan, PhD; Qi Sun, MD, ScD; Adam M. Bernstein, MD, ScD; Matthias B. Schulze, DrPH; JoAnn E. Manson, MD, DrPH; Meir J. Stampfer, MD, DrPH; Walter C. Willett, MD, DrPH; Frank B. Hu, MD, PhD

Background Red meat consumption has been associated with an increased risk of chronic diseases. However, its relationship with mortality remains uncertain.

Methods We prospectively observed 37 698 men from the Health Professionals Follow-up Study (1986-2008) and 83 644 women from the Nurses' Health Study (1980-2008) who were free of cardiovascular disease (CVD) and cancer at baseline. Diet was assessed by validated food frequency questionnaires and updated every 4 years.

Results We documented 23 926 deaths (including 5910 CVD and 9464 cancer deaths) during 2.96 million person-years of follow-up. After multivariate adjustment for major lifestyle and dietary risk factors, the pooled hazard ratio (HR) (95% CI) of total mortality for a 1-serving-per-day increase was 1.13 (1.07-1.20) for unprocessed red meat and 1.20 (1.15-1.24) for processed red meat. The corresponding HRs (95% CIs) were 1.18 (1.13-1.23) and 1.21 (1.13-1.31) for CVD mortality and 1.10 (1.06-1.14) and 1.16 (1.09-1.23) for cancer mortality. We estimated that substitutions of 1 serving per day of other foods (including fish, poultry, nuts, legumes, low-fat dairy, and whole grains) for 1 serving per day of red meat were associated with a 7% to 19% lower mortality risk. We also estimated that 9.3% of deaths in men and 7.6% in women in these cohorts could be prevented at the end of follow-up if all the individuals consumed fewer than 0.5 servings per day (approximately 42 g/d) of red meat.

Conclusions Red meat consumption is associated with an increased risk of total, CVD, and cancer mortality. Substitution of other healthy protein sources for red meat is associated with a lower mortality risk.

Meat is a major source of protein and fat in most diets. Substantial evidence from epidemiological studies shows that consumption of meat, particularly red meat, is associated with increased risks of diabetes,¹ cardiovascular disease (CVD),² and certain cancers.³ Several studies also suggest an elevated risk of mortality associated with red meat intake. However, most of these studies have been performed in populations with a particularly high proportion of vegetarians (such as Seventh-Day Adventists in the United States⁴ and several studies in Europe⁵). A recent large cohort study⁶ with 10 years of follow-up found that a higher intake of total red meat and total processed meat was associated with an increased risk of mortality. However, this study did not differentiate unprocessed from processed red meat, and diet and other covariates were assessed at baseline only. Furthermore, to our knowledge, no study has examined whether substitution of other dietary components for red meat is associated with a reduced mortality risk.

Therefore, we investigated the association between red meat intake and cause-specific and total mortality in 2 large cohorts with repeated measures of diet and up to 28 years of follow-up: the Health Professionals Follow-up Study (HPFS) and the Nurses' Health Study (NHS). We also estimated the associations of substituting other healthy protein sources for red meat with total and cause-specific mortality.

Perubahan lifestyle mencegah penuaan, penyakit dan 'premature morbidity'

The Lancet Oncology, Volume 14, Issue 11, Pages 1112 - 1120, October 2013

Effect of comprehensive lifestyle changes on telomerase activity and
telomere length in men with biopsy-proven low-risk prostate cancer:
5-year follow-up of a descriptive pilot study

Prof Dean Ornish MD et al

Background
Telomere shortness in human beings is a prognostic marker of ageing,
disease, and premature morbidity. We previously found an association
between 3 months of comprehensive lifestyle changes and increased
telomerase activity in human immune-system cells. We followed up
participants to investigate long-term effects.

Methods
This follow-up study compared ten men and 25 external controls who had
biopsy-proven low-risk prostate cancer and had chosen to undergo active
surveillance. Eligible participants were enrolled between 2003 and 2007
from previous studies and selected according to the same criteria. Men
in the intervention group followed a programme of comprehensive
lifestyle changes (diet, activity, stress management, and social
support), and the men in the control group underwent active surveillance
alone. We took blood samples at 5 years and compared relative telomere
length and telomerase enzymatic activity per viable cell with those at
baseline, and assessed their relation to the degree of lifestyle changes.

Findings
Relative telomere length increased from baseline by a median of 0·06
telomere to single-copy gene ratio (T/S)units (IQR—0·05 to 0·11) in the
lifestyle intervention group, but decreased in the control group (−0·03
T/S units, −0·05 to 0·03, difference p=0·03). When data from the two
groups were combined, adherence to lifestyle changes was significantly
associated with relative telomere length after adjustment for age and
the length of follow-up (for each percentage point increase in lifestyle
adherence score, T/S units increased by 0·07, 95% CI 0·02—0·12,
p=0·005). At 5 years, telomerase activity had decreased from baseline by
0·25 (—2·25 to 2·23) units in the lifestyle intervention group, and by
1·08 (—3·25 to 1·86) units in the control group (p=0·64), and was not
associated with adherence to lifestyle changes (relative risk 0·93, 95%
CI 0·72—1·20, p=0·57).

Interpretation
Our comprehensive lifestyle intervention was associated with increases
in relative telomere length after 5 years of follow-up, compared with
controls, in this small pilot study. Larger randomised controlled trials
are warranted to confirm this finding.

Children With Type 1 Diabetes Helped To Produce Their Own Insulin With Diet Additions

Adding foods rich in specific amino and fatty acids to the diets of youth with Type 1 diabetes kept them producing some of their own insulin for up to two years after diagnosis, said researchers at the Gillings School of Global Public Health at the University of North Carolina at Chapel Hill."

The youth still required supplemental insulin, but they may have reduced risk of diabetes complications by continuing to produce some of their own insulin, said Elizabeth Mayer-Davis, professor of nutrition at Gillings and medicine at UNC's School of Medicine, who led the study of more than 1,300 youth. "This also opens the door for a new approach that could really benefit the lives of these children."

The study, "Nutritional Factors and Preservation of C-Peptide in Youth with Recently Diagnosed Type 1 Diabetes," was published in the July 2013 issue of the journal Diabetes Care.

The participating youngsters, ranging from toddlers up to age 20, are part of a multi-center "SEARCH for Diabetes in Youth," the largest U.S. study of childhood diabetes. Mayer-Davis is national co-chair of SEARCH, funded by the national Centers for Disease Control and Prevention and the National Institutes of Health.

Type 1 diabetes is almost always diagnosed between infancy and young adulthood, according to the American Diabetes Association. The body's pancreas is unable to produce adequate amounts of the hormone insulin, required to metabolize food properly and create energy for the body's cells.

Leucine, one of the branched-chain amino acids researchers looked at, is known to stimulate secretion. It is found in dairy products, meats, soy products, eggs, nuts and products made with whole wheat. Long-chain omega-3 fatty acids are found in fatty fish such as salmon.

The researchers analyzed how much (if any) insulin the subjects were producing up to two years after their diagnosis and compared this with nutritional intake.

Mayer-Davis noted the study reflects subjects eating actual foods rich in these nutrients, not taking supplements.