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Asparagus allergy
664
Abstracts from the literature RED MEAT AND C O L O R E C T A L CANCER
ASPARAGUS ALLERGY
Epidemiologists have long linked high intakes of red meat with a raised risk of colorectal cancer, while more recently the molecular biologists have identified mutations in colorectal cancer cells characteristic of the action of alkylating agents such as N-nitroso compounds (NOC). A recent study in eight British men fed a diet high in red meat (600 g/day) for 3 wk found a significant increase in faecal NOC. The diets produced a dose of about ll0-140 pg NOC/day (about 30 #g/day of tobacco-specific carcinogenic NOC were said to be present in 40 cigarettes). Supplementing the high-red-meat diet with bran did not affect these raised levels. "This is the first demonstration in humans that intestinal N-nitrosation is raised when red meat intake is increased." The investigators concluded that "increased endogenous production of NOC and precursors from increased red meat.., consumption may be relevant to the aetiology of colorectal cancer" (Bingham et al., Carcinogenesis 1996, 17, 515).
Many cases of allergic contact dermatitis to asparagus have been reported in the literature. Investigators from Germany have now identified 1,2,3-trithiane-5-carboxylic acid--a constituent that regulates plant growth--as the allergen probably responsible. Four asparagus-sensitive patients were patch tested (24/48-hr covered contact) with fresh asparagus parts, juice, eight ether extracts, and four previously identified constituents. All reacted to 1,2,3-trithiane-5-carboxylic acid (1% in petrolatum) (Hausen and Wolf, American Journal of Contact Dermatitis' 1996, 7, 41).
COFFEE AND CORONARY HEART DISEASE A further 6 yr of observation of 38,500 Norwegians has markedly weakened an earlier reported association between coffee consumption and death from coronary heart disease (CHD). The cohort comprising both sexes has now been followed from screening in 1977-1982 up until the end of 1992, during which time there have been 476 CHD deaths. The association between risk of coronary death and coffee consumption was essentially absent when the first 6 yr of observation were excluded (Stensvold et al., British Medical Journal 1996, 312, 544). There was no association between coffee or caffeine intake and CHD in a cohort of 85,747 US women followed from 1980-1986 to mid-1990. A total of 712 cases of CHD (fatal and non-fatal) were documented. The investigators claimed this to be "the largest prospective cohort study to examine this relationship in women" and concluded that "coffee consumption is not an important cause of CHD among US women" (Willett et al., Journal of the American Medical Association 1996, 275, 458).
ANTICANCER ACTION OF BLACK AND GREEN TEAS A dose-dependent anticancer action has been reported for black tea. Mice received in their drinking water 0.63 or 1.25% decaffeinated tea (about 1 or 2.5 g/kg body weight/day) prior to, during, and after t r e a t m e n t with a standard liver and lung carcinogen. At the end of the 40-wk experiment there were clear reductions in the numbers of tumours at both sites. Green tea was also tested and exhibited a roughly similar level of protection (Cao et al., Fundamental and Applied Toxicology 1996, 29, 244).
BRAZIL-NUT ALLERGEN IN TRANSGENIC SOYBEANS
The possibilty that 'genetic engineering' may result in the transfer to novel foods of genes coding for allergenic proteins has been highlighted by US investigators. Antibodies in the serum of subjects with a known allergy to brazil nut were able to bind in culture with proteins not only from brazil nut itself, but also to a protein o f a (transgenic) soybean. In skin prick tests, three patients sensitive to brazil nut gave a similar response to extracts of the transgenic soybeans as to extracts of brazil nut, but gave no reaction to unaltered soybean. A brazil nut gene had been engineered into the soybean to improve its nutritional characteristics--the gene produced a protein, 2S albumin, a rich source of sulfurcontaining amino acids. Unfortunately this same protein was also probably allergenic (Nordlee et al., New England Journal of Medicine 1996, 334, 688). FLAVONOIDS AND CORONARY MORTALITY
A reduced death rate from heart disease in those with the higher dietary intakes of flavonoids has been reported in a cohort of over 5000 Finnish men a n d women. The participants who were in the age range 30 to 69 yr when first examined between 1967 and 1972, had been followed until 1992; by this time there had been over 1300 deaths, including 473 from heart disease. Normal consumption of flavonoids (quercetin, kaempferol, myricetin, luteolin and apigenin) was assessed by interview. The relative risks between the highest and lowest quartiles of flavonoid intake were 0.73 [95% confidence interval (CI) 0.41-1.32] and 0.67 (95% CI 0.44-1.00) for coronary mortality in men and women, respectively, after adjustment for intake of antioxidants. Intakes of onions and apples, the main dietary sources of flavonoids, presented similar associations (Knekt et al., Brit&h Medical Journal 1996, 312, 478), FOLIC ACID, FOLATEAND NEURAL TUBE DEFECTS The UK Department of Health (Doll) recommends that women at risk of becoming pregnant
Abstracts from the literature RED MEAT AND C O L O R E C T A L CANCER
ASPARAGUS ALLERGY
Epidemiologists have long linked high intakes of red meat with a raised risk of colorectal cancer, while more recently the molecular biologists have identified mutations in colorectal cancer cells characteristic of the action of alkylating agents such as N-nitroso compounds (NOC). A recent study in eight British men fed a diet high in red meat (600 g/day) for 3 wk found a significant increase in faecal NOC. The diets produced a dose of about ll0-140 pg NOC/day (about 30 #g/day of tobacco-specific carcinogenic NOC were said to be present in 40 cigarettes). Supplementing the high-red-meat diet with bran did not affect these raised levels. "This is the first demonstration in humans that intestinal N-nitrosation is raised when red meat intake is increased." The investigators concluded that "increased endogenous production of NOC and precursors from increased red meat.., consumption may be relevant to the aetiology of colorectal cancer" (Bingham et al., Carcinogenesis 1996, 17, 515).
Many cases of allergic contact dermatitis to asparagus have been reported in the literature. Investigators from Germany have now identified 1,2,3-trithiane-5-carboxylic acid--a constituent that regulates plant growth--as the allergen probably responsible. Four asparagus-sensitive patients were patch tested (24/48-hr covered contact) with fresh asparagus parts, juice, eight ether extracts, and four previously identified constituents. All reacted to 1,2,3-trithiane-5-carboxylic acid (1% in petrolatum) (Hausen and Wolf, American Journal of Contact Dermatitis' 1996, 7, 41).
COFFEE AND CORONARY HEART DISEASE A further 6 yr of observation of 38,500 Norwegians has markedly weakened an earlier reported association between coffee consumption and death from coronary heart disease (CHD). The cohort comprising both sexes has now been followed from screening in 1977-1982 up until the end of 1992, during which time there have been 476 CHD deaths. The association between risk of coronary death and coffee consumption was essentially absent when the first 6 yr of observation were excluded (Stensvold et al., British Medical Journal 1996, 312, 544). There was no association between coffee or caffeine intake and CHD in a cohort of 85,747 US women followed from 1980-1986 to mid-1990. A total of 712 cases of CHD (fatal and non-fatal) were documented. The investigators claimed this to be "the largest prospective cohort study to examine this relationship in women" and concluded that "coffee consumption is not an important cause of CHD among US women" (Willett et al., Journal of the American Medical Association 1996, 275, 458).
ANTICANCER ACTION OF BLACK AND GREEN TEAS A dose-dependent anticancer action has been reported for black tea. Mice received in their drinking water 0.63 or 1.25% decaffeinated tea (about 1 or 2.5 g/kg body weight/day) prior to, during, and after t r e a t m e n t with a standard liver and lung carcinogen. At the end of the 40-wk experiment there were clear reductions in the numbers of tumours at both sites. Green tea was also tested and exhibited a roughly similar level of protection (Cao et al., Fundamental and Applied Toxicology 1996, 29, 244).
BRAZIL-NUT ALLERGEN IN TRANSGENIC SOYBEANS
The possibilty that 'genetic engineering' may result in the transfer to novel foods of genes coding for allergenic proteins has been highlighted by US investigators. Antibodies in the serum of subjects with a known allergy to brazil nut were able to bind in culture with proteins not only from brazil nut itself, but also to a protein o f a (transgenic) soybean. In skin prick tests, three patients sensitive to brazil nut gave a similar response to extracts of the transgenic soybeans as to extracts of brazil nut, but gave no reaction to unaltered soybean. A brazil nut gene had been engineered into the soybean to improve its nutritional characteristics--the gene produced a protein, 2S albumin, a rich source of sulfurcontaining amino acids. Unfortunately this same protein was also probably allergenic (Nordlee et al., New England Journal of Medicine 1996, 334, 688). FLAVONOIDS AND CORONARY MORTALITY
A reduced death rate from heart disease in those with the higher dietary intakes of flavonoids has been reported in a cohort of over 5000 Finnish men a n d women. The participants who were in the age range 30 to 69 yr when first examined between 1967 and 1972, had been followed until 1992; by this time there had been over 1300 deaths, including 473 from heart disease. Normal consumption of flavonoids (quercetin, kaempferol, myricetin, luteolin and apigenin) was assessed by interview. The relative risks between the highest and lowest quartiles of flavonoid intake were 0.73 [95% confidence interval (CI) 0.41-1.32] and 0.67 (95% CI 0.44-1.00) for coronary mortality in men and women, respectively, after adjustment for intake of antioxidants. Intakes of onions and apples, the main dietary sources of flavonoids, presented similar associations (Knekt et al., Brit&h Medical Journal 1996, 312, 478), FOLIC ACID, FOLATEAND NEURAL TUBE DEFECTS The UK Department of Health (Doll) recommends that women at risk of becoming pregnant