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Soft drinks high blood pressure

Soft drinks high blood pressure

Drinking soft drinks is associated with higher blood pressure, according to a study of over 2,500 people reported this week in the journal Hypertension. High blood pressure is a major risk factor for heart disease, which is the leading cause of death worldwide. Someone with a blood pressure level in millimetres of mercury (mmHg) of 135 over 85 is twice as likely to have a heart attack or stroke as someone with a reading of 115 over 75.

The new research shows that for every extra can of soft drink consumed per day, participants on average had a higher systolic blood pressure by 1.6 mmHg and a higher diastolic blood pressure by 0.8 mmHg. This difference was statistically significant even after adjusting for factors such as weight and height. The study did not examine the mechanism that might link soft drinks with blood pressure. However, the researchers suggest that raised uric acid, which has been linked to soft drink consumption, might raise blood pressure by reducing the levels of nitric oxide, a chemical that relaxes the lining of the blood vessels.


The association between soft drinks and higher blood pressure was especially strong in people who consumed a lot of salt as well as sugar. Diet drinks were linked with lower blood pressure levels in some analyses, but the association was not consistent or strong. Professor Paul Elliott, senior author of the study, from the School of Public Health at Imperial College London, said: “It’s widely known that if you have too much salt in your diet, you’re more likely to develop high blood pressure. The results of this study suggest that people should be careful about how much sugar they consume as well.”

The researchers analysed data from 2,696 volunteers aged between 40 and 59, in eight areas of the US and two areas of the UK. On four separate occasions over a period of three weeks on average, the participants reported what they had eaten in the preceding 24 hours, as well as giving urine samples and having their blood pressure measured. The volunteers were taking part in INTERMAP, the International Study of Macronutrients, Micronutrients and Blood Pressure.

The researchers also found that people who drink more soft drinks tended to have more unhealthy diets in general. As well as consuming more sugar, those consuming more than one soft drink a day consumed more calories by 397 kilocalories per day on average, and less fibre and minerals. Those who did not consume soft drinks had a lower body mass index (BMI) on average than those who consumed more than one drink per day. “Individuals who drink a lot of sugar-sweetened beverages appear to have less healthy diets,” said Dr Ian Brown, the study’s first author, also from the School of Public Health at Imperial College London. “They are consuming empty calories without the nutritional benefits of real food. They consume less potassium, magnesium and calcium.” “This is a population study,” Dr Brown added. “It can’t say definitively that sugary drinks raise your blood pressure, but it’s one piece of the evidence in a jigsaw puzzle that needs to be completed. In the meantime, we would advise people who want to drink sugar-sweetened beverages should do so only in moderation.”


Can diet help with HIV?

On being asked about why she had decided to write a review, Dr Rayman replied: “There are three main reasons. First, to provide GPs and healthcare professionals with reliable information which could be used in treating patients and setting up healthcare programmes. Second, to raise concern that the levels of selenium are low in the UK and parts of Europe.

Third, to call for further research to clarify the optimal nutritional level with respect to selenium.” Dr Rayman explained that if, for example, there was further research to examine whether selenium as a nutrient could be helpful in slowing the progression of HIV to Aids, then it might provide a low cost solution in African countries particularly affected by HIV. The research so far had been carried out in the United States by Mariana Baum and colleagues of the University of Miami who found that HIV positive individuals have a twenty times greater chance of dying from Aids than those with adequate selenium levels. The Cancer Research Campaign is currently funding a £160,000 pilot study, which started in October 1999 led by Dr Rayman, and involves 500 people in the UK to see whether selenium can provide protection against cancer. This comes after an American study which showed encouraging health benefits for people who increased their daily intake of selenium. Dr Rayman said: “I am currently trying to raise £3.5m in funding to carry out a main UK study involving 10,000 people, when the pilot research finishes at the end of next year. It is essential to get sponsorship as scientific research is the only way to get positive proof of the health benefits of selenium. If a positive effect of selenium on cancer risk were to be established, the Government might then decide to act by adding selenium to the food supply. However, research is also needed to discover the optimal nutritional level with respect to selenium, because if people consume too much then it can become toxic”. Besides Britain, Sweden and Denmark are also taking part in the trial because of low dietary selenium. The US who are also participating in the study, have moderate selenium levels. The difference in countries' selenium levels depends on the amount of selenium present in the soil and which fertilisers are used. Finland has artificially added selenium to its fertilisers since 1984 to raise levels because of the reputed health benefit. In contrast, selenium levels in the UK have declined significantly over the last few decades – probably because we are no longer importing selenium-rich wheat from North America for use in our bread.