INTRODUCTION

Ramadan fasting can serve as an excellent research model for the study of human metabolism and behavior. One of the earliest published research findings on Ramadan fasting is from East Pakistan, now Bangladesh, reported by Muazzam and Khaleque (1). During the last twenty years there has been growing realization on the part of many scientists for further research in this area. Recently, a Ramadan fasting model has been used for various metabolic studies, Iraki et al (2), Ayabak et al (3), Husain et al. (4), Malik et al (5), El Ati et al (6), Nomani (7), Nomani et al (8), Sweileh et al (9) and Malhotra eta al (10) and for behavior modification, Afifi (11) Farren and Naidoo (12) and Daradkeh (13).

High blood cholesterol and uric acid have been considered health risk factors in cardiovascular diseases and gout, respectively. Conflicting results have been reported on the effect of dietary fat on changes in blood cholesterol levels, Gurr et al (14) and Kritchevsky (15). In 1979, Nomani et al (16) hypothesized that there is an increase in blood cholesterol levels with either increasing or decreasing level of energy intake in relation to the requirement. The recent findings of Ramadan fasting research, Nomani (7), Nomani et al (8) and Hallak and Nomani (17), confirm the hypothesis and help in resolving the dilemma of conflicting findings. The dietary regulation of blood cholesterol and uric acid levels are not only useful for Muslims but also for others throughout the world, irrespective of religion, race, color, gender or ethnic group.

According to the 1995 dietary guidelines, from the U. S. Department of Agriculture and Department of Health and Human Services (18) - energy from fat should not to be more than 30 percent, a level that is appropriate for the general population; however, this level may be inappropriate during Ramadan fasting or similar restricted energy intake situations. Under restricted energy intake conditions, such as Ramadan fasting, anorexia nervosa, prolonged weight control dieting and low energy intake conditions in underdeveloped or developing countries, there is a need for reassessment.

BLOOD CHOLESTEROL

Body weight

One of the major problems that contributes to conflicting results on the effect of quantity or quality of dietary fat on blood cholesterol level is a failure to examine the effect of dietary fat in relation to body weight or changes in body weight. There is an increase in blood cholesterol levels with increasing or decreasing weight from normal weight levels. Hallak and Nomani (17) noted increased blood cholesterol level with weight loss during the fasting month of Ramadan. Other investigators also noted increased blood cholesterol level with weight loss, Fedail et al. (19), Shoukry (20) and El Arnaoty and Johnson (21). Among non-Muslim American female subjects there was increase in blood cholesterol level with lowering of the body mass-index below 18.5, Nomani et al. (22). During Ramadan, when no significant difference was noticed in blood cholesterol levels, before and after fasting period, there was no significant difference in body weight as well, Maislos, et al (23).

Dietary fat and blood cholesterol level

Another omitted or insufficiently considered factor is statement of the energy intake in relation to the requirement. Under limited energy intake conditions, several studies on rats and humans, which include Muslims and non-Muslims, have indicated beneficial effects of a high fat-diet. In rats when the energy intake was ~70 percent of the requirement, blood cholesterol level was negatively associated with dietary fat energy, Nomani et al (24). In another study from the same laboratory, Forbes et al (25), found no significant difference in blood cholesterol levels of rats on diet with 40 percent of the total energy intake through fat (corn and coconut oils, 1.4:2) as compared to the group consuming 21 percent fat-energy from corn oil. Total energy intake was around 67-75 percent of the requirement. Further, this study indicates that there was significantly higher, p<0.05, nitrogen retention in the body in the high-fat diet group.

In humans, Murray et al (26) reported no significant difference between the mean blood cholesterol levels of Anagamba nomads, consuming 73% of the energy as fat, mainly from milk, and Kanouri sedentary men, both from East-Niger and of the same genetic stock, consuming only 9% of energy as fat. The total energy intake was around 18,00 kcal/day and mean weight of 52.3 kg and 51.4, respectively. Among Americans, Grundy (27) noted that when body weight was kept constant, a diet rich in monounsaturated fatty acids was as effective in lowering plasma cholesterol as was a diet low in fat and high in carbohydrate.

Hallak and Nomani (17) found that during the last two weeks of Ramadan fasting, when the subjects were on high-fat diets (1834 Kcal/day), there was no significant difference in blood cholesterol levels and body weights from beginning and end of this period. In another Ramadan study, when there was no significant change in body weight, Nomani et al. (8) noted change in serum cholesterol level inversely related to fat energy intake (coefficient of correlation, r = - 0.77, p<0.02). In a concave curve-linear model change in total-cholesterol: HDL-cholesterol ratio was the lowest and optimal at 36 percent of the energy from fat, coefficient of determination, r² = 0.86, p<0.01. In the multiple regression r² value further improved (0.98) with the inclusion of total energy intake, change in total-cholesterol: HDL-cholesterol = 4118.28 - 6.009 Fat, g/day - 3.077 Energy, Kcal/day. + 0.0007 Energy (Kcal/day)², p<0.001, Nomani (7). This suggest that fat and total energy level independently affected changes in the ratio. Maislos, et al (23) found that not only was there no significant difference in blood cholesterol level but the HDL-cholesterol profile improved during the fasting period. The dietary records were not available. However, the authors had the impression that the food consumed during Ramadan was of higher fat and carbohydrate content than that consumed during the rest of the year. In a recent study, El Ati et al. (6) showed that during Ramadan fasting the body develops adaptive mechanisms and there is an increased and decreased oxidation of fat and carbohydrate, respectively.

The findings of the above studies have lead to hypothesize that when energy is a limited, increased dietary fat level favors reduced breakdown of body protein, including labile proteins. Low-density lipoprotein (LDL) cholesterol-receptors , which are protein in nature, also may be affected. Thus, high-fat diet contributes in preventing the elevation of blood cholesterol level at restricted energy conditions, including Ramadan fasting. The findings have probable usefulness not only among Muslims observing Ramadan fast but also non-Muslims with anorexia nervosa, hospital in-patient subjects with low-weight or under-weight, populations in under-developed or developing countries, persons on prolonged low-calorie diets in weight-control programs and in many other situations with restricted energy intake conditions.

BLOOD URIC ACID

During Ramadan fasting increased blood uric acid have been observed by Fedail et al (19), El Ati et al (6), Gumaa et al (28), Nomani et al (29) and Al-Hader et al (30) . Nomani et al (29) noted change in blood uric levels negatively related to the changes in body weight, r = 0.52, p<0.05. In other words, increase in blood uric acid level was positively associated with body weight loss. During the last two weeks of Ramadan fasting, blood uric acid level in subjects with high uric acid level was prevented from further rise with the inclusion of high-fat diet, Nomani et al (7). Uric acid is a product of purine metabolism. Dietary-fat may be helpful in preventing the catabolism of these nitrogen containing compounds and protein during the fasting period. El Ati et al (6) noted the uric acid level returned back to normal one month after Ramadan period.

Summary

The findings of Ramadan fasting among Muslims and similar limiting energy intake situations among non-Muslims suggest that a high-fat diet around 36 percent of energy through fat, which includes poly-unsaturated fat, may be beneficial in preventing elevation of blood cholesterol or uric acid level and better retention of protein in the body.

Dr. Mohammad Zafar A. Nomani, is Professor Emeritus, West Virginia University;  and recipient of the first King Hassan II award for outstanding research contributions on Ramadan fasting, honored by Hassan II Foundation for Scientific and Medical Research on Ramadan, Casablanca, Morocco, at the First World Congress on Health and Ramadan.
Source: International Journal of Ramadan Fasting Research

REFERENCES

(1) Muazzam MG, Khaleque JA. Effect of fasting in Ramadan. The Journal of Tropical Medicine and Hygiene, 62:292-294, 1959.

(2) Iraki L, Bogdam A, Hakkou F, Amrani N, Abkari A, Touitou Y. Ramadan diet restrictions modify the circadian time structure in humans. A study on plasma gastrin, insulin, glucose, and calcium and on gastric pH. Journal of Clinical Endocrinolgy and Metabolism. 82:1261-73, 1997.

(3) Ayabak, M., A. Turkoglu, A. Sermet and O. Denli. Effect of Ramadan fasting on platelet aggregation in healthy male subjects. The European Journal of Applied Physiology, 73:552-556, 1996. 

(4) Husain R., Cheah SH, Duncan MT. Cardiovascular reactivity in Malay Moslems during Ramadan. Singapore Medical Journal. 37:398-401, 1996.

(5) Malik GM, Mubarik M, and Hussain T. Ramadan Fasting - Effects on Health and Disease. The Journal of the Association of Physicians of India, 44(5): 332-334, 1996.

(6) El Ati J, Beji C, Danguir J. Increased fat oxidation during Ramadan fasting in healthy women: an adaptive mechanism for body-weight maintenance. The American Journal of Clinical Nutrition, 62: 302-307, 1995.

(7) Nomani, MZA. Diet and changes in blood cholesterol and uric acid levels during Ramadan fasting. The Proceedings of the First International Congress on Health and Ramadan, Casablanca, Morocco, January 19-24, 1994, pp174-185.

(8) Nomani MZA, Baloch SK, Siddiqui IP. Change in serum cholesterol levels and dietary vegetable-fat at restricted energy intake condition during Ramadan fasting. The International Journal of Science and Technology, 4:30-36, 1992.

(9) Sweileh N, Schnitzler A, Hunter GR, Davis B. Body composition and energy metabolism in resting and exercising muslims during Ramadan fast. The Journal of Sports Medicine and Physical Fitness, 32(2): 156-163, 1992.

(10) Malhotra A, Scott PH, Scott J, Gee H, Wharton BA. Metabolic changes in Asian Muslim pregnant mothers observing Ramadan fast in Britain. British Journal of Nutrition. 61:663-672, 1989.

(11) Afifi ZEM. Daily practices, study of performance and health during the fast. The Journal of the Royal Society of Health, 117(4): 231; 1997.

(12) Farren C, Naidoo J. Smoking cessation programmes targeted at black and minority ethnic communities. The British Journal of Cancer, 74(Suppl. XXIX):S78-S80, 1996.

(13) Daradkeh TK. Parasuicide during Ramadan in Jordon. Acta Psychiatr Scan., 3:253-254, 1992.

(14) Gurr MI, Borlak N, Ganatra S. Dietary fat and plasma lipids. Nutrition Research Reviews. 2:63-86, 1989.

(15) Kritchevsky D. Dietary fibre and lipid metabolism. The International Journal of Obesity, 11(Suppl.)(1): 33-43, 1989.

(16) Nomani MZA, Albrink MJ, Davis GK, Lai HL, Watne AL. Changes in serum cholesterol with the variable digestibility of fiber diets at low energy intake. The Nutrition Reports International, 20:363-368, 1979.

(17) Hallak MH, Nomani MZA. Body-weight loss and changes in blood lipid levels in normal men on hypocaloric diets during Ramadan fasting. The American Journal of Clinical Nutrition, 1988; 48:1197-1210, 1988.

(18) US Department of Agriculture and US Department of Health and Human Services. Nutrition and Your Health: Dietary Guidelines for Americans, 4th edition. Home and Garden Bulletin No. 232. Washington, D.C. U.S., Govt. Printing Office, 1995.

(19) Fedail SS, Murphy D, Salih SY, Bolton CH, Harvey RF. Changes in certain blood constituents during Ramadan. The American Journal of Clinical Nutrition, 36:350-353, 1982 

(20) Shoukry MI. Effect of fasting in Ramadan on plasma lipo proteins and apoproteins. The Saudi Medical Journal, 6:561-5, 1986.

 (21) El-Arnoaty YM, Johnson WA. Nutritional and biochemical changes during Ramadan fasting. FASEB Journal, 1991; 5:(6)A1665 (Abstr.).

(22) Nomani MZA, Sypolt BL, Meegada PV, Brooks JL, Seime RJ, Vanin RR. Body mass index with reference to the least blood LDL-cholesterol level. The American Journal of Clinical Nutrition, 56:770, 1992. (Abstr.)

 (23) Maislos M, Khamaysi N, Assali A, Abou-Rabiah Y, Zvili I, Shany S. Marked increase in plasma high-density-lipoprotein cholesterol after prolonged fasting during Ramadan. The American Journal of Clinical Nutrition, 57:640-642, 1993.

(24) Nomani MZA, Hussain SS, Lim JK, Albrink MJ, Gunnels CK, Davis GK. Fecal bulk, energy intake, and serum cholesterol: regression response of serum cholesterol to apparent digestibility of dry matter and suboptimal energy intake in rats on fiber diet. The American Journal of Clinical Nutrition, 34: 2074-87, 1981.

 (25) Forbes BA, Nomani MZA, Mossahebi P, Salaita CG, Brooks JA, Loath MJ, Harvey JI. Coconut oil as a dietary supplement for weight gain without increasing blood cholesterol levels. The FASEB Journal, 11(3):A379, 1997.

 (26) Murray MJ, Murray AB, Murray NJ, Murray MB. Serum cholesterol, triglycerides and heart disease of nomadic and sedentary tribesman consuming isoenergetic diets of high and low fat content. The British Journal of Nutrition, 39:159-63, 1978.

 (27) Grundy, SM. Composition of monounsaturated fatty acids and carbohydrate for lowering plasma cholesterol. New England Journal of Medicine, 314:745-748, 1986.

 (28) Gumaa KA., Mustafa KY, Mahmoud NA, Gader AM. The effect of fasting in Ramadan. 1. Serum uric acid and lipid concentration. The British Journal of Nutrition, 40:573-80, 1978.

 (29) Nomani, MZA, Hallak MH, Siddiqui IP. Effect of Ramadan fasting on plasma uric acid and body weight in healthy men. The Journal of American Dietetic Association. 90:1435-1436, 1990.

 (30) Al-Hader AFA, Abu-Farsakh NA, Khatib SY, and Hasan ZA. The effect of Ramadan fasting on certain biochemical parameters in normal subjects and in type II diabetic patients. Annals of Saudi Medicine, 14(2): 139-141, 1994.