Nutritional and food protection against epidemic emerging neuropathy. Epidemiological findings in the unique disease-free urban area of Cuba.

A survey was conducted through the SECUBA (SEguridad alimentaria en CUba y Buena Alimentación) research program in Cuban healthy smokers living in Guantánamo and in Havana. The aim of the survey was to investigate biological and nutritional factors connected with the occurrence of zero epidemic neuropathy (EN) observed in Guantánamo urban area since the disease emerged in Cuba. Blood riboflavin status and carotenoid and selenium concentrations were higher in Guantánamo than in Havana smokers. Food dietary quantities of plantain banana, pepper (Capsicum spp.), bovine meat and milk products were higher in Guantánamo. Inversely, foods rich in cholesterol, especially eggs, were more consumed in Havana. Through riboflavin, carotenoid and selenium contents and specific antioxidants substances (indoleamines, capsaicin), the foods more consumed in Guantánamo could be considered as EN protective factors. Disease protective effects could be exerted via enhancement of defence mechanisms against free radical damage and related mechanisms focused on redox recycling of glutathione and local protection from carotenoids. Finally, the results of the present study should help Cuba, through a better EN control, to improve long-term food safety and define healthier dietary habits.

Relation between serum lipoperoxide concentrations and iron or copper status over one year in Cuban adult men.

The aims of this study were to determine the relations between iron and copper status and lipid peroxidation at different periods over one year in low-income and low-energy intake healthy subjects. The study was conducted in 199 middle-aged healthy Cuban men from March 1995 to February 1996. Iron status was assessed by the determination of serum ferritin, transferrin saturation, whole blood hemoglobin and iron intakes. Copper status was evaluated by the determination of serum copper and copper intakes. Serum thiobarbituric acid substances (TBARS) determination was used as an index of lipid peroxidation. Rank correlations were observed between serum TBARS concentrations and iron or copper status indices at different periods. In period 3 (end of the rainy season), serum TBARS and ferritin concentrations were maximum whereas blood hemoglobin levels and iron intake were minimum. Serum TBARS concentrations were significantly higher than the reference values of the laboratory whereas, iron and copper status were within the reference ranges. These results suggested that iron and copper status may be associated with lipid peroxidation in subjects without metal overloads and that variations over the year needed to be taken in account.

Vitamin B intake and status in healthy Havanan men, 2 years after the Cuban neuropathy epidemic.

A prospective epidemiological study was carried out over 1 year to evaluate vitamin B complex dietary intake and status in Cuba, 2 years after the Cuban neuropathy epidemic of 1993. Of the 199 healthy middle-aged men selected, 141 completed the study. Volunteers were followed up every 3 months for 1 year. Dietary intake and status of thiamin, riboflavin, vitamin B6, folate and vitamin B12 were assessed each time. The dietary intake of vitamin B complex was low, particularly in June and July (folate), and October (thiamin). A deficient status was observed for vitamin B complex, except for vitamin B6. Vitamin B complex intake and status varied over the year. However, dietary intake and status were poorly related. The results prove that healthy Cuban men represent a vulnerable population in terms of vitamin B complex status and stress the necessity to both promote preventive multivitamin supplementation and produce local food rich in vitamin B complex.

Seasonal variations of antioxidant imbalance in Cuban healthy men.

OBJECTIVE: To determine the antioxidant imbalance in healthy Cuban men 2y after the end of the epidemic neuropathy (50 862 cases from 1991 to 1993) and to evaluate its change over 1 y. DESIGN: Prospective study. SETTING: La Lisa health centres (Havana, Cuba). SUBJECTS: One-hundred and ninety-nine healthy middle-aged men were selected and 106 completed the study. Subjects were studied at 3 month intervals over 1 year. INTERVENTIONS: No invervention. MAIN OUTCOME MEASURES: An assessment of dietary intake and the determination of blood lipid peroxides (TBARS), glutathione, diglutathione, glutathione peroxidase, superoxide dismutase, vitamin E, carotenoids, copper, zinc and selenium were performed at each period. RESULTS: While dietary zinc, vitamins C and E, carotenoids and fat dietary intakes and blood concentrations were low for adult men compared to international reference ranges, serum TBARS concentrations were high at every period. Some significant seasonal variations were observed. The lowest carotenoids (P < 0.002) and vitamin C(P = 0.0001) intakes, serum beta-carotene (P = 0.0001) and lutein/zeaxanthin (P < 0.05) concentrations, and the highest blood TBARS (P = 0.0001) and diglutathione (P < 0.001) concentrations were observed at the end of the rainy season (October). This period seemed to pose the greatest risk of antioxidant imbalance. CONCLUSIONS: Cuban men still represent a vulnerable population in terms of antioxidant imbalance. A national program of vegetable growing and increase in fruit and vegetable consumption is now evaluated in Cuba.

Vitamin and nutritional status in Cuban smokers and nonsmokers in the context of an emerging epidemic neuropathy.

A prospective survey was conducted in a random sample of smokers (SMO) and non-smokers (NON) men living in Havana. The aim of the survey was to investigate metabolic and dietary parameters discriminating between SMO and NON volunteers, which could explain underlying mechanisms to the higher risk of Epidemic Neuropathy (51,000 reported cases in Cuba from late 1991) previously demonstrated in the Cuban smoker. Forty three blood markers were determined and dietary intakes evaluated during 4 seasonal periods. alpha-carotene, beta-carotene, beta-cryptoxanthin, total carotenoids and riboflavin blood concentrations were lower in SMO vs. NON subjects. Activities of glutathione reductase and butryrylcholinesterase were lower in the SMO group, as did total protein levels. Copper and thiocyanates were higher in SMO subjects. Most of the dietary parameters did not differ between the two groups of volunteers. Low biologically available quantities of carotenoids and riboflavin from low dietary intakes and depletion through smoking would be the main precipitating factors of Epidemic Neuropathy. Protein depletion and copper delivery via tobacco smoke, sunlight exposure, level of physical activity and high consumption of cigarettes, in a context of low dietary supplies concerning especially B vitamins, were probably aggravating factors through oxidative stress and impairment of cyanide detoxification.

Fate in humans of dietary intake of cyanogenic glycosides from roots of sweet cassava consumed in Cuba.

We studied if consumption of boiled fresh roots from sweet cassava varieties grown in Cuba resulted in exposure to cyanogenic glycosides and their final breakdown product, cyanide. When adult, nonsmoking subjects consumed 1-4 kg cassava over 2 days, their urinary levels of the main cyanide metabolite, thiocyanate, only increased from a mean +/- SEM of 12 +/- 2 to 22 +/- 2 mumol/l, indicating a negligible cyanide exposure. Their mean urinary linamarin, the main cyanogenic glucoside in cassava, increased from 2 +/- 1 to 68 +/- 16 mumol/l. In a second experiment 5 subjects consumed one meal of 0.5 kg boiled cassava that contained 105 mumol linamarin and 8 mumol hydrogen cyanide (HCN). Quantitative urine collections prior to and after intake showed that 28% of linamarin was excreted during the following 24 hours, whereas a modest increase of urinary thiocyanate (SCN) only corresponded to the small amount of free HCN ingested. These results indicate that the dominant cyanogen in boiled cassava is glycosides that pass through the human body without causing cyanide exposure. It remains to be studied whether humans occasionally possess intestinal or tissue beta-glucosidases that can hydrolyse cyanogenic glycosides from cassava.