Article 1

  Garlic & Onions offer Protection against Cancer

Thursday 18th May 2006

An article in the International Journal of Cancer (2006, 118 (10): 2559 - 2566) provides information on the relationship between fruit and vegetable (F&V) intake and the risk of developing gastric and oesophageal cancer, gleaned from the huge EPIC study. On a related topic, Angelo De Martino and colleagues at the University of Rome have investigated the effects of an aqueous garlic extract on liver cancer cells.

Carlos Gonzalez led a large multinational team of authors who examined data from 521,457 men and women enrolled in the European Prospective Investigation into Cancer and Nutrition (EPIC), and drawn from 10 countries. Information on diet and lifestyle was collected at baseline. After an average of 6.5 years of follow-up, 330 cases of gastric cancer were confirmed and 65 cases of adenocarcinoma of the oesophagus. A sub-sample of subjects was examined for antibodies to Helicobacter pylori.

Gonzalez reported that they observed no association between total F&V intake or intake of specific groups of vegetables and gastric cancer risk, except for the intestinal type of gastric cancer where a negative association was possible between total vegetable intake and onion and garlic intake. There was no evidence of a link between fresh fruit intake and gastric cancer risk. A negative but non-significant association between citrus fruit intake and cardia-type gastric cancer was observed. With regard to oesophageal cancer, a non-significant negative association was found with respect to vegetable and citrus fruit intakes. H. pylori infection did not modify the effect of F&V intake. (Summary in NutraIngredients.com).

De Martino et al. prepared water extracts from fresh garlic bulbs which had come from two geographic locations in Italy and added them to cultures of human liver cancer cells (HepG2 hepatoma cells). The effects of the fresh garlic extracts on the cancer cells were compared with control cells to which nothing had been added and the effects of diallyl disulphide (DADS), a derivative of allicin which gives garlic its distinctive aroma and flavour. After 48 hours of incubation, the control liver cancer cells had increased by 300%. DADS, under the experimental conditions used, was not detrimental to the HepG2 cells. However, a 1% solution of the two garlic extracts inhibited tumour growth completely. The garlic extracts acted in a time-and dose-dependent manner on cell proliferation with a significant reduction in the number of viable cells after 24 hours, with a less pronounced recovery of cell proliferation at 48 hours. The compounds in the garlic extract responsible for the observed effects were not identified and, according to the authors, further metabolomic studies are needed to establish this. (From the Journal of Nutritional Biochemistry, article in press; summary in NutraIngredients.com 04/05/06 ).

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Article 2

Vitamin D may reduce inflammation in heart disease patients

Wednesday 19th of April 2006

 

Survival rates five years after a first diagnosis of congestive heart failure are only 35 - 50%. Previously in vitro studies have suggested that vitamin D may suppress proinflammatory cytokines and increase anti-inflammatory cytokines. Since elevated circulating pro-inflammatory cytokines are thought to contribute to the pathogenesis of congestive heart failure, Stefanie Schleithoff and colleagues from the University of Bonn, Germany, investigated the effects of vitamin D on 123 patients with this condition.

The subjects were divided into an intervention group and a placebo group. The intervention group received 50 ìg vitamin D3/day plus 500 mg calcium/day for nine months. The placebo group also received 500 mg calcium/day for nine months. Biochemical variables were assessed at baseline and at the end if the study period. The survival rate was assessed for a follow up period of 15 months.

Results indicated that a daily supplement of 50 ìg of vitamin D for nine months was able to increase serum concentrations of the anti-inflammatory cytokine IL-10 and to prevent an increase in serum concentrations of the pro-inflammatory cytokine TNF- á (tumour necrosis factor á) in congestive heart failure patients. Moreover, the suppression in serum PTH (para-thyroid hormone) concentrations was more pronounced in the vitamin D supplemented group. However, the survival rate during follow up was similar in both groups. It should also be mentioned that in vitro studies have shown that the release of TNF- á can be suppressed by calcitriol in a dose-dependent manner. Immune cells are able to make calcitriol from circulating 25(OH)D (serum vitamin D)

The authors concluded that the results of their study offered interesting therapeutic options for diseases such as congestive heart failure. The authors do, however, point out certain limitations of the study. Firstly, the concentrations of supplemental vitamin D were probably too low to optimise all vitamin D dependent functions. Also, due to the poor health of the volunteers in this study the number of drop outs was relatively high. The patients who dropped out generally had higher serum PTH concentrations and lower 25(OH)D concentrations at baseline. Finally, the calcium supplementation may have influenced cardiac function in both study groups. Nevertheless, Schleithoff et al. explain why they believe it would have been unethical to not have supplemented both groups with calcium in their paper published in The American Journal of Clinical Nutrition, 83 (4), 2006; pp 754 -759