Physiology and Biochemistry 279
Changes in Plasma Lipoprotein Levels during a Hiking Expedition in South America M Faber1, A. J. Spinnier Benadé1 , C. Celliers2 , M Marais1 'Research Institute for Nutritional Diseases of the South African Medical Research Council, P. 0. Box 19070, Tygberberg, 7505, Republic of South Africa 2Chamber of Mines of South Africa, Johannesburg
during a hiking expedition lasting several weeks, many Mi Faber, A. J. Spinnier Benadé, C. Ce/hers and M. Marais, Changes in Plasma Lipoprotein Levels during a Hiking Expedition in South America. mt i Sports Med, Vol 13, No 4, pp 279—284, 1992.
Accepted after revision: October 19, 1991
Eleven males participated in a hiking expedition over a period of 6 weeks during which they walked an average of 15 km per day, resting days included. The partic-
ipants completed a seven-day estimated dietary record before and during the expedition. Their habitual dietary intake before the expedition was typical of a Western diet. During the expedition most animal products, with the exception of canned fish, were excluded from the diet. The dietary intake of fat and carbohydrate changed from 36.9% and 40.6% to 14.0% and 76.4% respectively. Cholesterol intake dropped from 557 mg to 92 mg. Mean plasma total cholesterol (TC) decreased from 190.9 mg/100 ml to 142.0 mg/i 00 ml. These changes were mainly due to changes in
low density lipoprotein cholesterol (LDL-C). Although high density lipoprotein cholesterol (HDL-C) did not change, the ratio of HDL-C to TC increased significantly. It
can be concluded that drastic dietary changes, together with increased physical activity and weight loss resulted in
major plasma lipoprotein changes. The expected fall in HDL-C due to a high carbohydrate diet was counteracted
L
by the increased physical activity and weight loss. Key words
Hiking expedition, walking, physical activity, dietary intake, plasma lipids
Introduction
Increased physical activity has been shown to decrease plasma total cholesterol (TC) levels (20; 29; 38) and increase plasma high density lipoprotein cholesterol (HDL-C) levels (23; 24; 32; 37; 38). This is especially true for endurance exercise such as running (40). In general it can be said that lnt.J.SportsMed. 13(1992)279284 GeorgThieme Verlag Stuttgart New York
kilometers are covered by walking continuously. The effect of this kind of prolonged low intensity exercise over a period of
several weeks on plasma lipids is not known. A short term study in which the subjects walked 37km for each of 4 successive days showed that very low density lipoprotein cholesterol (VLDL-C) decreased and HDL-C increased when the subjects
consumed a mixed diet (48.3% carbohydrates; 36.7% fat; 15% protein). When they, however, consumed a high carbohydrate (CHO) diet, there was a decrease in HDL-C levels, suggesting that dietary changes can strongly influence the changes
that occur in plasma lipoprotein concentrations during prolonged low-intensity exercise (14). Not only does the physical activity pattern change during a hiking expedition, but dietary changes also occur. Non-perishable products such as cereals, texturised protein and canned foods are used. The result is that
meat and meat products as well as fresh milk and milk products such as cheese are usually excluded from the diet (dried and canned products can be consumed). The cholesterol, animal protein and fat intake (especially saturated fat) is therefore very low. It has been shown that a reduction in cholesterol and fat intake result in lower plasma TC levels (16). During a
hiking expedition, fat in the diet is replaced by CHO. It has been shown that replacement of fat by CHO lowers HDL-C (3; 15; 16). What the combined effect is of the prolonged low intensity physical activity for several weeks together with the low fat, low cholesterol and low animal protein diet is, is not known. Methods
Background information The party consisted of 24 persons (18 males and 6 females). Due to technical reasons the results of only eleven of the males will be reported in this paper. They were be-
tween the ages of 25 and 44 years (mean= 31.4; SD = 6.1). During the expedition, which lasted 6 weeks, they walked an average of 15 km per day (resting days included). The duration
of the walk was on average approximately 5 hours per day. Their habitual physical activity pattern before the expedition varied from sedentary to running 12 km per day. Each party member carried a weight of approximately 25 kg. Dried food such as Pro-nutro (a cereal), oats, Toppers (texturised soya protein), Lebnor (texturised soya protein) and Smash (dehydrated mashed potatoes) of a weight of 10 kg was taken along. In the mountains there were shops that provided food such as sugar, rice, pasta, soup powder, condensed milk, biscuits and cold drinks. Fresh fruit was sometimes available but it was not carried along with them.
Downloaded by: National University of Singapore. Copyrighted material.
Abstract
mt. J. Sports Med. 13 (1992,)
Anthropometric Measurements The subjects were weighed in light clothing to the nearest 0.05 kg and height was taken to the nearest 0.1 cm. The first measurement was taken 4 days before the expedition
started and the second measurement was taken at the end of the expedition. Percentage bodyfat was determined by the method described by Copley, 1983 (7).
Mi Faber, A. J. Spinnier Benadé, C. Celliers, Mi Marais
tions. Samples of control serum (Boehringer Mannheim GmbH, catalogue number 125067) were included in each batch of samples analysed for cholesterol and triglyceride con-
tent.
The combined very low density lipoprotein (VLDL) and intermediate density lipoprotein (IDL) (density range 1.006—1.063 g/ml) were separated by sequential prepa-
rative ultracentrifugation with density adjustments using Dietary Information Dietary information was collected using the 7 day estimated dietary record method. Data was obtained 4 weeks before the expedition as well as at the end of the expedition (before the blood sample was taken). Recordings were made on standard forms. A detailed instruction list was given to each participant. The amount of food eaten was reported in household measures, e. g. standard cups or tablespoons, or the dimensions of the food eaten were given. If the weight of the food was known to the subject, it was recorded. All quantities
of food consumed were converted to grams and computer coded. The weight of the volumes and houshold measuretnents were controlled by using the NRIND Food Quantities Manual (28), a manual which gives the weights for all the items
included in the NRIND Food Composition Tables. Different household measurements (e. g. 1 heaped teaspoon, I level tablespoon, — cup etc.) of the food items are listed against the weight of the food item. The food items were then computer coded. Nutrient intake was analyzed by computer using the NRIND Food Composition Tables 1986 (13). This paper will report only the macro-nutrient intake.
Blood sampling and analysis
A fasting blood sample was taken 4 weeks before the expedition as well as directly after the expedition. Both blood samples were taken in the morning after an overnight fast. The second blood sample was taken the day after they had completed the walk to the hospital where the blood sampling was done. Fasting blood samples (20 ml blood) were drawn from the antecubital vein into vacutainer tubes contain-
tng EDTA (1 mg/mi) as anticoagulant. The subjects were seated during blood sampling. The blood was kept on ice until it was centrifuged at 3000 rpm for 15 mm. The plasma was used for the isolation of the different lipid fractions. Plasma triacyl-
glycerol (TAG) was measured by the fully enzymatic UV method Test combination (Boehringer Mannheim, catalogue number 240052). Plasma total cholesterol (TC) was determined by the high performance CHOD-PAP enzymatic colorimetric method (Boehringer Mannheim, catalogue number 237574). High density lipoproteins (HDL) were separated
by precipitating the Apo B containing lipoproteins in the plasma with heparin manganese chloride (12). The total cholesterol content of HDL (HDL-C) was determined by an enzymatic iodide method (E Merck, Darmstadt, catalogue number 14350). Apolipoproteins Al and All were measured nephelometrically directly on the plasma. Antibodies against human apolipoproteins were used for Apo Al (Boehringer
Mannheim, Catalogue number 726478) and Apo Al 1 (726479). Apo B was measured in the plasma nephelometrically using antiserum against human apolipoprotein B (Boehringer Mannheirn GmbH, Catalogue number 726494). Standardized human serum was used as standard for measuring all apolipoproteins and cholesterol in the plasma and HDL frac-
NaBr (17). A fixed angle 40.3 rotor was used in a Beckman L8
80 M ultracentrifuge, at 10 °C, 40000 rpm. Two spins of 20 hours each were done. Total cholesterol of the VLDL + IDL and the LDL fractions was determined using an enzymatic iodide method as for the HDL fractions.
Haemoglobin concentrations were determined before and after the expedition with a Compur D2 mini-
photometer (Compur-Electronic GmbH, München, Germany). These haemoglobin concentrations were used to calculate any changes in blood volume by the method described by Dill and Costill, 1974 (10).
Statistical analysis The mean and standard deviation (SD) for the anthropometric, dietary and plasma lipid values were calculated. The Student's t-test for paired observations was used to determine whether there was a difference between the values before and during the expedition. The percentage change in plasma lipids and dietary factors was calculated. The Spearman correlation coefficient was determined between these percentage changes in plasma lipids and dietary factors. Results
Anthropometry The mean height of the subjects was 179.4 cm (SD = 6.6). Before the expedition they weighed a mean of 73.8 kg (SD = 6.9) and six weeks later (after the expedition) they weighed 68.2 kg (SD = 6.2). This change in weight is statistically significant at the p < 0.01 level. Percentage bodyfat changed from 14.5% (SD =4.01) to 11.82% (SD== 3.64).
This change in percentage bodyfat is significant at the p
Changes in Plasma Lipoprotein Levels during a Hiking Expedition in South America M Faber1, A. J. Spinnier Benadé1 , C. Celliers2 , M Marais1 'Research Institute for Nutritional Diseases of the South African Medical Research Council, P. 0. Box 19070, Tygberberg, 7505, Republic of South Africa 2Chamber of Mines of South Africa, Johannesburg
during a hiking expedition lasting several weeks, many Mi Faber, A. J. Spinnier Benadé, C. Ce/hers and M. Marais, Changes in Plasma Lipoprotein Levels during a Hiking Expedition in South America. mt i Sports Med, Vol 13, No 4, pp 279—284, 1992.
Accepted after revision: October 19, 1991
Eleven males participated in a hiking expedition over a period of 6 weeks during which they walked an average of 15 km per day, resting days included. The partic-
ipants completed a seven-day estimated dietary record before and during the expedition. Their habitual dietary intake before the expedition was typical of a Western diet. During the expedition most animal products, with the exception of canned fish, were excluded from the diet. The dietary intake of fat and carbohydrate changed from 36.9% and 40.6% to 14.0% and 76.4% respectively. Cholesterol intake dropped from 557 mg to 92 mg. Mean plasma total cholesterol (TC) decreased from 190.9 mg/100 ml to 142.0 mg/i 00 ml. These changes were mainly due to changes in
low density lipoprotein cholesterol (LDL-C). Although high density lipoprotein cholesterol (HDL-C) did not change, the ratio of HDL-C to TC increased significantly. It
can be concluded that drastic dietary changes, together with increased physical activity and weight loss resulted in
major plasma lipoprotein changes. The expected fall in HDL-C due to a high carbohydrate diet was counteracted
L
by the increased physical activity and weight loss. Key words
Hiking expedition, walking, physical activity, dietary intake, plasma lipids
Introduction
Increased physical activity has been shown to decrease plasma total cholesterol (TC) levels (20; 29; 38) and increase plasma high density lipoprotein cholesterol (HDL-C) levels (23; 24; 32; 37; 38). This is especially true for endurance exercise such as running (40). In general it can be said that lnt.J.SportsMed. 13(1992)279284 GeorgThieme Verlag Stuttgart New York
kilometers are covered by walking continuously. The effect of this kind of prolonged low intensity exercise over a period of
several weeks on plasma lipids is not known. A short term study in which the subjects walked 37km for each of 4 successive days showed that very low density lipoprotein cholesterol (VLDL-C) decreased and HDL-C increased when the subjects
consumed a mixed diet (48.3% carbohydrates; 36.7% fat; 15% protein). When they, however, consumed a high carbohydrate (CHO) diet, there was a decrease in HDL-C levels, suggesting that dietary changes can strongly influence the changes
that occur in plasma lipoprotein concentrations during prolonged low-intensity exercise (14). Not only does the physical activity pattern change during a hiking expedition, but dietary changes also occur. Non-perishable products such as cereals, texturised protein and canned foods are used. The result is that
meat and meat products as well as fresh milk and milk products such as cheese are usually excluded from the diet (dried and canned products can be consumed). The cholesterol, animal protein and fat intake (especially saturated fat) is therefore very low. It has been shown that a reduction in cholesterol and fat intake result in lower plasma TC levels (16). During a
hiking expedition, fat in the diet is replaced by CHO. It has been shown that replacement of fat by CHO lowers HDL-C (3; 15; 16). What the combined effect is of the prolonged low intensity physical activity for several weeks together with the low fat, low cholesterol and low animal protein diet is, is not known. Methods
Background information The party consisted of 24 persons (18 males and 6 females). Due to technical reasons the results of only eleven of the males will be reported in this paper. They were be-
tween the ages of 25 and 44 years (mean= 31.4; SD = 6.1). During the expedition, which lasted 6 weeks, they walked an average of 15 km per day (resting days included). The duration
of the walk was on average approximately 5 hours per day. Their habitual physical activity pattern before the expedition varied from sedentary to running 12 km per day. Each party member carried a weight of approximately 25 kg. Dried food such as Pro-nutro (a cereal), oats, Toppers (texturised soya protein), Lebnor (texturised soya protein) and Smash (dehydrated mashed potatoes) of a weight of 10 kg was taken along. In the mountains there were shops that provided food such as sugar, rice, pasta, soup powder, condensed milk, biscuits and cold drinks. Fresh fruit was sometimes available but it was not carried along with them.
Downloaded by: National University of Singapore. Copyrighted material.
Abstract
mt. J. Sports Med. 13 (1992,)
Anthropometric Measurements The subjects were weighed in light clothing to the nearest 0.05 kg and height was taken to the nearest 0.1 cm. The first measurement was taken 4 days before the expedition
started and the second measurement was taken at the end of the expedition. Percentage bodyfat was determined by the method described by Copley, 1983 (7).
Mi Faber, A. J. Spinnier Benadé, C. Celliers, Mi Marais
tions. Samples of control serum (Boehringer Mannheim GmbH, catalogue number 125067) were included in each batch of samples analysed for cholesterol and triglyceride con-
tent.
The combined very low density lipoprotein (VLDL) and intermediate density lipoprotein (IDL) (density range 1.006—1.063 g/ml) were separated by sequential prepa-
rative ultracentrifugation with density adjustments using Dietary Information Dietary information was collected using the 7 day estimated dietary record method. Data was obtained 4 weeks before the expedition as well as at the end of the expedition (before the blood sample was taken). Recordings were made on standard forms. A detailed instruction list was given to each participant. The amount of food eaten was reported in household measures, e. g. standard cups or tablespoons, or the dimensions of the food eaten were given. If the weight of the food was known to the subject, it was recorded. All quantities
of food consumed were converted to grams and computer coded. The weight of the volumes and houshold measuretnents were controlled by using the NRIND Food Quantities Manual (28), a manual which gives the weights for all the items
included in the NRIND Food Composition Tables. Different household measurements (e. g. 1 heaped teaspoon, I level tablespoon, — cup etc.) of the food items are listed against the weight of the food item. The food items were then computer coded. Nutrient intake was analyzed by computer using the NRIND Food Composition Tables 1986 (13). This paper will report only the macro-nutrient intake.
Blood sampling and analysis
A fasting blood sample was taken 4 weeks before the expedition as well as directly after the expedition. Both blood samples were taken in the morning after an overnight fast. The second blood sample was taken the day after they had completed the walk to the hospital where the blood sampling was done. Fasting blood samples (20 ml blood) were drawn from the antecubital vein into vacutainer tubes contain-
tng EDTA (1 mg/mi) as anticoagulant. The subjects were seated during blood sampling. The blood was kept on ice until it was centrifuged at 3000 rpm for 15 mm. The plasma was used for the isolation of the different lipid fractions. Plasma triacyl-
glycerol (TAG) was measured by the fully enzymatic UV method Test combination (Boehringer Mannheim, catalogue number 240052). Plasma total cholesterol (TC) was determined by the high performance CHOD-PAP enzymatic colorimetric method (Boehringer Mannheim, catalogue number 237574). High density lipoproteins (HDL) were separated
by precipitating the Apo B containing lipoproteins in the plasma with heparin manganese chloride (12). The total cholesterol content of HDL (HDL-C) was determined by an enzymatic iodide method (E Merck, Darmstadt, catalogue number 14350). Apolipoproteins Al and All were measured nephelometrically directly on the plasma. Antibodies against human apolipoproteins were used for Apo Al (Boehringer
Mannheim, Catalogue number 726478) and Apo Al 1 (726479). Apo B was measured in the plasma nephelometrically using antiserum against human apolipoprotein B (Boehringer Mannheirn GmbH, Catalogue number 726494). Standardized human serum was used as standard for measuring all apolipoproteins and cholesterol in the plasma and HDL frac-
NaBr (17). A fixed angle 40.3 rotor was used in a Beckman L8
80 M ultracentrifuge, at 10 °C, 40000 rpm. Two spins of 20 hours each were done. Total cholesterol of the VLDL + IDL and the LDL fractions was determined using an enzymatic iodide method as for the HDL fractions.
Haemoglobin concentrations were determined before and after the expedition with a Compur D2 mini-
photometer (Compur-Electronic GmbH, München, Germany). These haemoglobin concentrations were used to calculate any changes in blood volume by the method described by Dill and Costill, 1974 (10).
Statistical analysis The mean and standard deviation (SD) for the anthropometric, dietary and plasma lipid values were calculated. The Student's t-test for paired observations was used to determine whether there was a difference between the values before and during the expedition. The percentage change in plasma lipids and dietary factors was calculated. The Spearman correlation coefficient was determined between these percentage changes in plasma lipids and dietary factors. Results
Anthropometry The mean height of the subjects was 179.4 cm (SD = 6.6). Before the expedition they weighed a mean of 73.8 kg (SD = 6.9) and six weeks later (after the expedition) they weighed 68.2 kg (SD = 6.2). This change in weight is statistically significant at the p < 0.01 level. Percentage bodyfat changed from 14.5% (SD =4.01) to 11.82% (SD== 3.64).
This change in percentage bodyfat is significant at the p
