Uncontrolled high blood pressure? Skip the salt

NEW YORK (Reuters Health) — People who have uncontrolled high blood pressure despite taking multiple blood pressure-lowering drugs can lower their blood pressure by adopting a low-salt diet, according to a study released today at the American Heart Association's 62nd Annual Fall Conference of the Council for High Blood Pressure Research in Atlanta.

"A high-salt diet contributes importantly to treatment-resistant hypertension (high blood pressure)," Dr. Eduardo Pimenta from the Dante Pazzanese Institute of Cardiology, Sao Paulo, Brazil, told Reuters Health.

Pimenta and colleagues measured the impact of a restricted-salt diet on 24-hour blood pressure readings, obtained using a recorder worn continuously for 24 hours, in 13 adults with treatment-resistant hypertension. In a "crossover" study, low- and high-salt diets were tested for seven days separated by a two-week "washout" period, after which the subjects switched groups.

The patients were taking an average of 3.6 blood pressure lowering medications and had an average "office" blood pressure of 147.9 over 85.2 millimetres of mercury (mmHg). Normal blood pressure is 140 over 90 mmHg.

According to Pimenta and colleagues, the amount of sodium excreted in urine over 24-hours was markedly reduced during the low-salt diet compared to the high-salt diet.

Moreover, on the low-salt diet, systolic blood pressure — the top number in blood pressure readings that represent pressure while the heart contracts — was reduced by 22.6 mmHg, while diastolic blood pressure — the bottom number that gives the pressure when the heart relaxes between beats — was lower by 9.2 mmHg.

"We were expecting blood pressure reduction with low-salt diet but the reduction was larger than we expected," Pimenta admitted.

The study also confirms that a high-salt diet can impair blood vessel function and cause people to retain fluid "despite diuretic therapy," Pimenta said. During the low-salt diet, healthy reductions in the fluid volume were seen. This research, the study team concludes, clearly demonstrates the harmful effects of a high-salt diet in people with stubborn hypertension, as well as the benefits of a low-salt diet.

Antioxidant skin cream blocks UV damage

NEW YORK (Reuters Health) — A cream containing vitamin C, vitamin E and ferulic acid protects the skin from sun damage and reduces cancer-associated mutations in skin cells, new research shows.

The cream's "mechanism of action is different from sunscreens and would be expected to supplement the sun protection provided by sunscreens," Dr. Sheldon R. Pinnell of Duke University Medical Center in Durham, North Carolina and colleagues write. Pinnell is a consultant to SkinCeuticals-L'Oreal, which makes the cream and also helped to fund the study.

Ultraviolet radiation damages the skin by causing oxidative stress, Pinnell and his team note, and they have been investigating topical applications of antioxidants for neutralising this damage.

In previous research, they demonstrated that vitamin C and vitamin E were individually effective for boosting antioxidant protection, and even more effective when used together. In subsequent laboratory studies, they showed that ferulic acid, a plant antioxidant, increased the antioxidant effects of the vitamins even further.

In the current study, the researchers report on the effects of a cream containing 15 percent vitamin C, one percent vitamin E, and 0.5 percent ferulic acid on human skin. They applied the cream to nine white adults and then exposed them to simulated sun irradiation.

Compared to a cream with no active ingredients, the ferulic acid cream reduced skin redness after sun exposure and caused fewer skin cells to sunburn. The active cream almost completely blocked the production of thymine dimers, a type of UV-related genetic damage, as well as the induction of the tumour suppressor gene p53.

While unprotected skin exposed to UV radiation produced substances called cytokines that promote inflammation and suppress immune system function, protected skin did not.