Jack L. Smith

Serum Levels of Vitamin C in Relation to Dietary and Supplemental Intake of Vitamin C in Smokers and Nonsmokers

Serum vitamin C levels were compared in smokers and nonsmokers in relation to dietary and supplemental intake of vitamin C, using data from the Second National Health and Nutrition Examination Survey. Smokers reported a lower mean daily intake (53 mg) of vitamin C than nonsmokers (65 mg) and a higher percentage (41% compared to 31%) consuming less than 70% RDA. Smoking status of respondents was judged by carboxyhemoglobin levels or by questionnaire. With both methods, percent of nonsupplemented smokers with serum vitamin C 0.3 mg/dl or less was two or more times as high as nonsupplemented nonsmokers at similar dietary intake levels. When smokers and nonsmokers with similar dietary vitamin C intake were ranked by serum C level, median and mean serum C for smokers was consistently lower than nonsmokers by approximately 0.2 mg/dl. By using the parallel bioassay methods, it was estimated that smokers would need an additional 59 mg/day dietary vitamin C (95% confidence interval of 52-68 mg/day) based on median values or 65 mg/day (53-79 mg/day) based on mean values to attain serum C levels comparable to nonsmokers.

Exercise training effects on serum lipids of prepubescent boys and adult men

The effects of 10 wk of exercise training at low (40% VO2max) or high (75% VO2max) intensity on serum lipids and lipoproteins were compared in prepubescent boys and adult men. The final sample size consisted of: 8 boys (mean +/- SE age = 8.5 +/- 1.96 yr) and 8 men (36.6 +/- 3.18 yr) in low; 12 boys (8.0 +/- 1.40 yr) and 12 men (36.6 +/- 4.09 yr) in high; and 10 boys (9.0 +/- 2.08 yr) and 10 men (36.7 +/- 4.82 yr) in control. Training involved walking/jogging/running 3 d X wk-1 at a distance which progressed from 2.4 km X d-1 in the first week to 4.8 km X d-1 from the fifth week. Fasting blood samples, collected on 2 d during both pre- and post-training, were assayed for triglycerides, total cholesterol (CHOL), and high density lipoprotein cholesterol (HDL-C). Maximum aerobic power (VO2max) was determined from a treadmill test. Additionally, dietary intake was assessed from a 3-d dietary record and body composition from the sum of 6 skinfolds. The only statistically significant (P less than 0.05) changes occurred in HDL-C and CHOL for the high groups. HDL-C decreased following training. CHOL was lower for high than the other groups for the first day post-training only. There were no differences in the changes in HDL-C/CHOL ratio among the groups. VO2max only increased in the high groups. Dietary intake and body weight did not change. Further statistical adjustment in lipids for changes in sum of 6 skinfolds did not alter the results.(ABSTRACT TRUNCATED AT 250 WORDS)

Developing an elementary school CHD prevention program

In brief: Sixty-three students aged 7 to 12 years (32 boys, 31 girls) were assessed for coronary heart disease (CHD) risk factors, including family history of CHD, blood pressure, VO2 max, serum lipids, body composition, and history of diabetes mellitus and cigarette smoking. Forty-two percent of the children had one risk factor, and 12% and 3% had two and three risk factors, respectively. This information was used to encourage school administrators and faculty to modify the physical education program, teach health and fitness concepts in the classroom, and develop a rehabilitation program for children at risk.

Urinary Alkalinization and Smoking Cessation.

Previous studies have shown that large doses of a urinary alkalinizing agent reduced cigarette consumption spontaneously among smokers. After establishing a safe daily dose of an alkalinizing agent, sodium bicarbonate, its effect upon smoking cessation rates among 72 enrollees in a smoking cessation program was studied. In the first study, we determined that sodium bicarbonate (3900 mg per day) significantly increased urinary pH (from 6.0 to 6.7) and lowered titratable acidity. Ascorbic acid (1500 mg per day) had no effect of pH or acidity. In a second study, a group given sodium bicarbonate surpassed a placebo control group (who were given 1500 mg per day ascorbic acid) in total daily cigarette reduction after 5 weeks and in week-to-week smoking reduction. The groups did not, however, differ in the number who achieved total abstinence.