Friday, July 24, 2009

Low-carb vs high-carb terhadap BB dan profil lipid

Diet rendah karbohidrat tinggi protein hewani (Atkins) dapat menurunkan berat badan (BB) namun terhadap kolesterol LDL (LDL-C) pengaruhnya kurang baik. Dalam penelitian ini protein hewani diganti bahan nabati (diet "Eco-Atkins" atau Atkins nabati) kemudian dibandingkan dengan diet tinggi karbohidrat dalam hal menurunkan BB dan LDL-C.
 
Diet Atkins nabati mengandung 26% karbohidrat, 31% protein nabati dan 43% minyak nabati.
Diet tinggi karbohidrat lakto-ovo vegetarian mengandung 58% karbohidrat, 16% protein dan 25% lemak.
 
Dilakukan studi paralel selama 4 minggu.
 
Hasilnya: dalam hal penurunan BB kedua diet sama (turun 4.0 kg). Dalam hal penurunan LDL, rasio total kolesterol-HDL, rasio apolipoprotein B-apolipoprotein AI lebih besar diet rendah karbohidrat (masing2 –8.1% [P = .002], –8.7% [P = .004], and –9.6% [P = .001] ). Juga terjadi penurunan tekanan sistolik dan diastolik (masing2 –1.9% [P = .052] and –2.4% [P = .02] ).
 
Kesimpulan diet rendah karbohidrat protein nabati (Atkins nabati) lebih unggul dibanding diet tinggi karbohidrat dalam hal memperbaiki faktor risiko kardiovaskuler. Hal mana tidak terjadi pada diet Atkins. 
 
The Effect of a Plant-Based Low-Carbohydrate ("Eco-Atkins") Diet on Body Weight and Blood Lipid Concentrations in Hyperlipidemic Subjects

David J. A. Jenkins, MD; Julia M. W. Wong, RD; Cyril W. C. Kendall, PhD; Amin Esfahani, MSc; Vivian W. Y. Ng, RD; Tracy C. K. Leong, BASc; Dorothea A. Faulkner, PhD; Ed Vidgen, BSc; Kathryn A. Greaves, PhD; Gregory Paul, PhD; William Singer, MD

Arch Intern Med. 2009;169(11):1046-1054.

Background  Low-carbohydrate, high–animal protein diets, which are advocated for weight loss, may not promote the desired reduction in low-density lipoprotein cholesterol (LDL-C) concentration. The effect of exchanging the animal proteins and fats for those of vegetable origin has not been tested. Our objective was to determine the effect on weight loss and LDL-C concentration of a low-carbohydrate diet high in vegetable proteins from gluten, soy, nuts, fruits, vegetables, cereals, and vegetable oils compared with a high-carbohydrate diet based on low-fat dairy and whole grain products.

Methods  A total of 47 overweight hyperlipidemic men and women consumed either (1) a low-carbohydrate (26% of total calories), high–vegetable protein (31% from gluten, soy, nuts, fruit, vegetables, and cereals), and vegetable oil (43%) plant-based diet or (2) a high-carbohydrate lacto-ovo vegetarian diet (58% carbohydrate, 16% protein, and 25% fat) for 4 weeks each in a parallel study design. The study food was provided at 60% of calorie requirements.

Results  Of the 47 subjects, 44 (94%) (test, n = 22 [92%]; control, n = 22 [96%]) completed the study. Weight loss was similar for both diets (approximately 4.0 kg). However, reductions in LDL-C concentration and total cholesterol–HDL-C and apolipoprotein B–apolipoprotein AI ratios were greater for the low-carbohydrate compared with the high-carbohydrate diet (–8.1% [P = .002], –8.7% [P = .004], and –9.6% [P = .001], respectively). Reductions in systolic and diastolic blood pressure were also seen (–1.9% [P = .052] and –2.4% [P = .02], respectively).

Conclusion  A low-carbohydrate plant-based diet has lipid-lowering advantages over a high-carbohydrate, low-fat weight-loss diet in improving heart disease risk factors not seen with conventional low-fat diets with animal products.

 

Thursday, July 9, 2009

Alcohol 'flush' signals cancer risk in Asians

Orang Asia timur yang mengalami flush saat minum alkohol menghadapi risiko kanker esofagus bila minum banyak alkohol.
Hal ini disebabkan kurangnya enzim ALDH2 yang mengubah acetaldehyde menjadi acetate (bentuk senyawa aman).
Mereka yang mempunyai defisiensi gen ALDH2 mengalami flushing, mual dan takikardia bila meminum alkohol.
36% orang Asia timur mempunyai defisiensi gen ALDH2.
 
 
Alcohol 'flush' signals cancer risk in Asians
David Brill
Medical Tribune
 
East Asians who "flush" when drinking alcohol could be at increased risk of esophageal cancer if they do not drink responsibly, a recent study has warned.
 
The characteristic red cheeks and nausea are a well-recognized phenomenon, but few people are aware that the underlying enzyme deficiency also predisposes heavy drinkers to squamous cell esophageal carcinoma, say the researchers.
 
With some 36 percent of East Asians displaying the flush response, there is potential to save "a substantial number of lives" by counseling affected individuals against heavy drinking. [PLoS Med 2009 Mar 24;6(3):e50]
 
"Cancer of the esophagus is particularly deadly, with 5-year survival rates ranging from 12 to 31 percent throughout the world," said lead researcher Dr. Philip Brooks, of the US National Institute on Alcohol Abuse and Alcoholism. "And we estimate that at least 540 million people have this alcohol-related increased risk for esophageal cancer.
 
"We hope that by raising awareness of this important public health problem, affected individuals who drink will reduce their cancer risk by limiting their alcohol consumption," he said.
 
Flushing is caused by a deficiency in aldehyde dehydrogenase 2 (ALDH2) – an enzyme which breaks down acetaldehyde, a carcinogenic by-product of ethanol metabolism. People with normal ALDH2 function can convert acetaldehyde safely into acetate, but in ALDH2-deficient individuals it accumulates in the body, leading to facial redness, nausea and tachycardia.
 
In people who are homozygous for the ALDH2-deficiency gene, the response to alcohol is so unpleasant that they cannot consume large quantities, and are thereby protected from the associated risk of esophageal cancer.
 
Heterozygotes, however, can develop tolerance to acetaldehyde and may become heavy drinkers. Studies from Japan and Taiwan have shown that ALDH2-deficient heterozygotes who drink heavily are over 10 times as likely to develop esophageal cancer, [Jpn J Clin Oncol 2003 Mar;33(3):111-21; Int J Cancer 2008 Mar 15;122(6):1347-56]
 
Dr. Michael Wang, a radiation oncology consultant at the National Cancer Centre Singapore, agreed that the link between flushing and esophageal cancer is not likely to be common knowledge among doctors.
 
"From the article, it is fair to comment that there is a causative relation between deficiency of the gene and increased risk of esophageal cancer," he said.
 
"However, there has been a lot of material published since the 1970s regarding this condition. This relationship may be confounded by smoking, which is also related to esophageal cancer. Before we say something drastic like 'people who flush when drinking have a higher risk of contracting esophageal cancer,' we should research all the previously published articles."
 
Wang added that all heavy alcohol drinkers should be counseled, since drinking also predisposes people to other medical conditions and to drunk driving.
 
The study authors advise clinicians to determine whether East Asian patients are ALDH2 deficient by asking simple questions about their history of flushing when drinking alcohol. Identified flushers should then be advised of their cancer risk and encouraged to moderate their consumption, they say.