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Potassium Intake, Stroke, and Cardiovascular Disease A Meta-Analysis of Prospective Studies
J Am Coll Cardiol, 2011; 57:1210-1219           Lanfranco D’Elia

Objectives:

The objective of this study was to assess the relation between the level of habitual potassium intake and the incidence of cardiovascular disease (CVD).

Background:

Prospective cohort studies have evaluated the relationship between habitual potassium intake and incidence of vascular disease, but their results have not been not entirely consistent.

Methods:

We performed a systematic search for prospective studies published, without language restrictions (1966 to December 2009). Criteria for inclusion were prospective adult population study, assessment of baseline potassium intake, assessment of vascular events as outcome, and follow-up of at least 4 years. For each study, relative risks (RRs) and 95% confidence intervals (CIs) were extracted and pooled using a random-effect model, weighted for the inverse of the variance. Heterogeneity, publication bias, subgroup, and meta-regression analyses were performed.

Results:

Eleven studies were identified, providing 15 cohort samples that included 247,510 male and female participants (follow-up 5 to 19 years), 7,066 strokes, 3,058 coronary heart disease (CHD) events, and 2,497 total CVD events. Potassium intake was assessed by 24-h dietary recall (n = 2), food frequency questionnaire (n = 6), or 24-h urinary excretion (n = 3). In the pooled analysis, a 1.64-g (42 mmol) per day higher potassium intake was associated with a 21% lower risk of stroke (RR: 0.79; 95% CI: 0.68 to 0.90; p = 0.0007), with a trend toward lower risk of CHD and total CVD that attained statistical significance after the exclusion of a single cohort, based on sensitivity analysis (RR: 0.93; 95% CI: 0.87 to 0.99; p = 0.03 and RR: 0.74; 95% CI: 0.60 to 0.91; p = 0.0037).

Conclusions:

Higher dietary potassium intake is associated with lower rates of stroke and might also reduce the risk of CHD and total CVD. These results support recommendations for higher consumption of potassium-rich foods to prevent vascular diseases.

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Exposure to Room Light before Bedtime Suppresses Melatonin Onset and Shortens Melatonin Duration in Humans
The Journal of Clinical Endocrinology & Metabolism, Vol. 96 (3): 463-472 2011 Joshua J. Gooley

Context:

Millions of individuals habitually expose themselves to room light in the hours before bedtime, yet the effects of this behavior on melatonin signaling are not well recognized.

Objective:

We tested the hypothesis that exposure to room light in the late evening suppresses the onset of melatonin synthesis and shortens the duration of melatonin production.

Design:

In a retrospective analysis, we compared daily melatonin profiles in individuals living in room light (<200 lux) vs. dim light (<3 lux).

Healthy volunteers (n = 116, 18–30 yr) were recruited from the general population to participate in one of two studies.

Participants lived in a General Clinical Research Center for at least five consecutive days.

Individuals were exposed to room light or dim light in the 8 h preceding bedtime.

Melatonin duration, onset and offset, suppression, and phase angle of entrainment were determined.

Compared with dim light, exposure to room light before bedtime suppressed melatonin, resulting in a later melatonin onset in 99.0% of individuals and shortening melatonin duration by about 90 min. Also, exposure to room light during the usual hours of sleep suppressed melatonin by greater than 50% in most (85%) trials.

These findings indicate that room light exerts a profound suppressive effect on melatonin levels and shortens the body’s internal representation of night duration. Hence, chronically exposing oneself to electrical lighting in the late evening disrupts melatonin signaling and could therefore potentially impact sleep, thermoregulation, blood pressure, and glucose homeostasis.

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Influence of acetaminophen and ibuprofen on skeletal muscle adaptations to resistance exercise in older adults
Todd A. Trappe AJP - Regu Physiol March 2011 vol. 300 no. 3 R655-R662

Evidence suggests that consumption of over-the-counter cyclooxygenase (COX) inhibitors may interfere with the positive effects that resistance exercise training has on reversing sarcopenia in older adults. This study examined the influence of acetaminophen or ibuprofen consumption on muscle mass and strength during 12 wk of knee extensor progressive resistance exercise training in older adults. Thirty-six individuals were randomly assigned to one of three groups and consumed the COX-inhibiting drugs in double-blind placebo-controlled fashion: placebo (67 ± 2 yr; n = 12), acetaminophen (64 ± 1 yr; n = 11; 4 g/day), and ibuprofen (64 ± 1 yr; n = 13; 1.2 g/day). Compliance with the resistance training program (100%) and drug consumption (via digital video observation, 94%), and resistance training intensity were similar (P > 0.05) for all three groups. Drug consumption unexpectedly increased muscle volume (acetaminophen: 109 ± 14 cm3, 12.5%; ibuprofen: 84 ± 10 cm3, 10.9%) and muscle strength (acetaminophen: 19 ± 2 kg; ibuprofen: 19 ± 2 kg) to a greater extent (P

< 0.05) than placebo (muscle volume: 69 ± 12 cm3, 8.6%; muscle strength: 15 ± 2 kg), when controlling for initial muscle size and strength. Follow-up analysis of muscle biopsies taken from the vastus lateralis before and after training showed muscle protein content, muscle water content, and myosin heavy chain distribution were not influenced (P >

0.05) by drug consumption. Similarly, muscle content of the two known enzymes potentially targeted by the drugs, COX-1 and -2, was not influenced (P > 0.05) by drug consumption, although resistance training did result in a drug-independent increase in COX-1 (32 ± 8%; P

< 0.05). Drug consumption did not influence the size of the nonresistance-trained hamstring muscles (P >

0.05). Over-the-counter doses of acetaminophen or ibuprofen, when consumed in combination with resistance training, do not inhibit and appear to enhance muscle hypertrophy and strength gains in older adults. The present findings coupled with previous short-term exercise studies provide convincing evidence that the COX pathway(s) are involved in the regulation of muscle protein turnover and muscle mass in humans.

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Use of dietary supplements by cardiologists, dermatologists and orthopedists: report of a survey
Annette Dickinson, Andrew Shao, Nicolas Boyon and Julio C. Franco Nutrition Journal 2011, 10:20 doi:10.1186/1475-2891-10-20

Dietary supplements are regularly used by a majority of the American population, and usage by health professionals is also common. There is considerable interest in usage patterns within the population and in the reasons for using dietary supplements. The “Life…supplemented” Healthcare Professionals 2008 Impact Study (HCP Impact Study) surveyed usage of dietary supplements by physicians in three specialties: cardiology, dermatology, and orthopedics.

Methods

The HCP Impact Study was conducted online by Ipsos Public Affairs for the Council for Responsible Nutrition (CRN), a trade association of the dietary supplement industry. Respondents were 900 physicians, including 300 each from three specialties - cardiology, dermatology, and orthopedics.

Results

Fifty-seven percent of cardiologists said they use dietary supplements at least occasionally, as did 75% of dermatologists and 73% of orthopedists.
The product most commonly reported to be used was a multivitamin, but over 25% in each specialty said they used omega-3 fatty acids and over 20% said they used some botanical supplements. Regular dietary supplement use was reported by 37% of cardiologists, 59% of dermatologists, and 50% of orthopedists. Seventy-two percent of cardiologists, 66% of dermatologists, and 91% of orthopedists reported recommending dietary supplements to their patients. The primary reason given for recommending dietary supplements to patients was for heart health or lowering cholesterol for the cardiologists; benefits for skin, hair and nails for the dermatologists; and bone and joint health for the orthopedists.

Conclusions

Reported dietary supplement use was relatively common in this sample of physicians, and when they recommended dietary supplements to patients, they tended to do so for reasons related to their specialty.

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Effects of high-whey-protein intake and resistance training on renal, bone and metabolic parameters in rats
Virginia A. Aparicio British Journal of NutritionBritish Journal of Nutrition (2011), 105: 836-845

Consumption of high-protein (HP) diets is postulated to exert a negative influence on bone and renal health. However, no conclusive evidence has been presented related to this issue or to the potential protective action of resistance training on HP-induced systemic effects. We examined the effects of HP diet consumption on food intake, body-weight gain, body composition, and renal, bone and metabolic parameters of rats performing resistance training. A total of ninety-six adult male Wistar rats were randomly distributed in twelve experimental groups (n 8): normal-protein (10 %) or HP (45 %) diets, with or without resistance training, killed for experimental periods of 1, 2 or 3 months. Diets were based on a commercial whey protein hydrolysate. Consumption of HP diets and resistance training significantly affected food intake, body weight and body composition, as well as the plasma levels of total cholesterol, HDL-cholesterol and TAG. The buffering action of resistance training on such diet-induced alterations was especially evident in the levels of plasma TAG. Consumption of HP diets led to a considerable increase in kidney weight, urinary volume and acidity, as well as in the urinary excretion of Ca, with a parallel reduction in the urinary excretion of citrate (P < 0·05). No apparent deleterious effect on bone mineral content was found. In conclusion, consumption of HP diets caused alterations in renal health status and some metabolic parameters, but did not seem to affect bone status. Resistance training had a protective action against alterations of renal health status and some metabolic parameters such as plasma TAG.

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