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.”
Scientists may have discovered a way of identifying dieters who are prone to piling the pounds back on after weight loss. A study at Maastricht University’s Department of Human Biology found a link between a gene involved in regulating blood pressure and post-diet weight gain in women. Women who regained weight after slimming had a high change in the concentration of a particular protein in their blood during dieting, research showed. Researchers now hope to develop a test to indicate how prone people are to yo-yo dieting.
Edwin Mariman, professor of functional genetics at Maastricht, said: “It was a surprising discovery, because until now there has been no clear link between this protein and obesity. “We do not yet have an explanation for the results, but it does appear that it should be possible within a few years to use this finding to develop a test to show who is at high risk of putting weight back on after a diet.”
Hospitals already conduct tests for the protein, known as the angiotensin I converting enzyme (ACE). But the test is currently carried out to check its activity in regulating blood pressure, rather than its concentration. Up 80% of dieters suffer from the yo-yo effect, returning to their original weight within a year.
The study looked at around 100 women aged 20 to 45, half of whom had maintained their post-diet weight and half of whom had put weight back on. The findings of the research have been published by Dr Ping Wang, a scientist in Professor Mariman’s research group, in the online scientific journal PloS ONE.
Starting the morning with a bowl of porridge and eating a whole-grain sandwich at lunchtime can help cut the risk of high blood pressure, according to new research. A study carried out by scientists from Aberdeen University which involved more than 200 volunteers revealed that eating three portions of whole-grain foods every day lowers the risk of high blood pressure, a major risk factor for heart disease and stroke. A good deal of research has suggested that a whole-grain diet is good for your health, but this study is one of the first to test the theory in a well-designed clinical trial.
Volunteers in the study ate three servings a day of whole-grain foods, which were either wheat, or a mixture of both wheat and oats. The whole-grain diets were compared with one that contained the same amounts of refined cereals and white bread. The study used foods widely available in supermarkets to make the diet easy to follow, without having to make any changes to their usual lifestyle. Apart from the whole-grain and the equivalent refined cereal foods, the volunteers were encouraged to continue with their normal food choices.
Dr Frank Thies, senior lecturer at The Rowett Institute of Nutrition and Health, who led the study, said: “We observed a decrease in systolic blood pressure of 5-6 mm Hg in the volunteers who ate the whole-grain foods, and this effect is similar to that you might expect to get from using blood pressure-lowering drugs. “This drop in systolic blood pressure could potentially decrease the incidence of heart attack and stroke disease by at least 15 and 25 per cent respectively. The scientists also added that wholegrain wheat and oat-based recipes should be on everyone's festive menu this Christmas.
The findings are published in the American Journal of Clinical Nutrition.
The researchers also looked at the overall health profiles of rice eaters, and learned that the 19- to 50-year-olds who ate rice were less likely to be overweight or obese, had a 34% reduced risk for high blood pressure, 27% reduced likelihood of having abdominal obesity and increased waist circumference and 21% reduced risk of metabolic syndrome. No associations could be drawn for children ages two to 13; however, in children ages 14-18, body weight, waist circumference, triglycerides and diastolic blood pressure were lower (P G .05) among those who ate rice.
“This study shows that eating rice can improve overall diet and reduce risk for the major conditions that afflict more than half of all Americans — heart disease and Type II diabetes,” states Upton. “Rice is a practical solution to help consumers meet dietary guidance to eat more plant-based foods.”
U.S. national nutrition surveillance records show that rice eaters have healthier diets and less risk for chronic diseases compared to non-rice eaters. The researchers reported that rice eaters are:
- 1/3 less likely to have high blood pressure;
- 1/4 less likely to have a high waist circumference (often linked to obesity and diabetes risk);
- 1/5 less likely to have metabolic syndrome.
Research shows U.S. rice consumption has increased steadily over the past 20 years, with current per capita consumption at 26 pounds per person. Surveys show that rice is most frequently served as a side dish or one pot meal.
The research was supported by a grant from the USA Rice Federation.
Supplementing diet with whey-based protein may help reduce high blood pressure, a U.S. researcher says.
Nutritional biochemist Susan Fluegel of Washington State University in Spokane says daily doses of commonly available whey brought a more than 6-point reduction in the average blood pressure of men and women with elevated systolic and diastolic blood pressures. Whey is a by-product of cheese-making. “One of the things I like about this is it is low-cost,” Fluegel says in a statement. “Not only that, whey protein has not been shown to be harmful in any way.”
The study, published in International Dairy Journal, finds not everyone drinking the whey-supplemented drink has changes in blood pressure.
The supplement did not lower the blood pressure of subjects who did not have elevated pressure to begin with. That's good, says Fluegel, since low blood pressure can also be a problem. However, blood-pressure reductions — as seen in those with elevated pressure in this study — can bring a 35 percent to 40 percent reduction in fatal strokes, says Fluegel.
Fluegel and colleagues looked at 71 student subjects ages 18-26, but Fluegel says older people with blood pressure issues would likely get similar results. The supplement was delivered in fruit-flavored drinks developed at the university's creamery.
The researchers analyzed data from the National Health and Nutrition Examination Survey (2003-2006) which consisted of 4,528 US adults 18 years of age or older that had no previous hypertension diagnosis. The survey asked about dietary habits and what foods and beverages that they consumed. The researchers said that those who ate 74 grams (about 2.5 cans of sugared soda) or more each day of fructose sugar, had shown an increased risk for developing hypertension. There was a 26 percent chance for these individuals to have high blood pressure reading at 135/85mmHg , a 30 percent higher risk to have high blood pressure measured at 140/90, and a 77 percent higher risk for having blood pressure measured at 160/100 mmHg. A normal blood pressure reading is under 120/80 mmHg.
The researchers point out that even though this shows a potential trigger for high blood pressure, a randomized clinical study would need to be conducted in order to prove that a low fructose diet would prevent hypertension.
Beetroot juice, a source of high nitrate levels, may help prevent high blood pressure, according to a study published in Hypertension. Nitrate is a compound that increases the amount of gas nitric oxide that circulates through the blood.In an effort to determine if beetroot juice contains enough nitrate to lower blood pressure, researchers had two groups of individuals either drink the juice or take nitrate capsules.
The results of the study showed that within 24 hours, the supplements and the juice had lowered the blood pressure of people in both groups. Furthermore, the investigators discovered that about 250 mL of beetroot juice was all that was needed to have the same effects on one's blood pressure as the nitrate capsules.
These findings showed that “beetroot and nitrate capsules are equally effective in lowering blood pressure, indicating that it is the nitrate content of beetroot juice that underlies its potential to reduce blood pressure,” said Amrita Ahluwalia, lead researcher of the study.
Dr. Topping urges the government and legislative bodies to encourage people to incorporate these in their diets. “All of this adds up to a very impressive body of evidence which helps to support our push as nutritionists but also as members of other bodies to encourage the government and health authorities to get them to encourage the population to eat more [grains],” he said.
Head of Go Grains Dr Michele Allan also says that this is an easy way of disease prevention. “You're looking at less medication, less visits to the doctor and also if you've got a calorie-controlled diet and an increase to four-plus serves of grains and legumes a day, you actually reduce weight over a period of time,” she said.
In all, researchers say the study demonstrates that a grape-enriched diet can have broad effects on the development of heart disease and metabolic syndrome and the risk factors that go along with it.
“The possible reasoning behind the lessening of metabolic syndrome is that the phytochemicals were active in protecting the heart cells from the damaging effects of metabolic syndrome. In the rats, inflammation of the heart and heart function was maintained far better,” says Steven Bolling, M.D., heart surgeon at the U-M Cardiovascular Center and head of the U-M Cardioprotection Research Laboratory.
The researchers also looked for signs of inflammation, oxidative damage and other molecular indicators of cardiac stress. Again, the rats who consumed the grape powder had lower levels of these markers than rats who did not receive grapes.
There is no well-accepted way to diagnose metabolic syndrome which is really a cluster of characteristics: excess belly fat (for men, a waist measuring 40 inches or more and for women, a waist measuring 35 inches or more); high triglycerides which can lead to plague build-up in the artery walls; high blood pressure; reduced glucose tolerance; and elevated c-reactive protein, a marker for inflammation in the body.
Those with metabolic syndrome are at higher risk for cardiovascular disease and type 2 diabetes.
But the U-M study suggests that it may be possible that grape consumption can change the downhill sequence that leads to heart disease by prolonging the time between when symptoms begin to occur and a time of diagnosis.
“Reducing these risk factors may delay the onset of diabetes or heart disease, or lessen the severity of the diseases,” says E. Mitchell Seymour, Ph.D., lead researcher and manager of the U-M Cardioprotection Research Laboratory. “Ultimately it may lessen the health burden of these increasingly common conditions.”
Rats were fed the same weight of food each day, with powered grapes making up 3 percent of the diet. Although the current study was supported in part by the California Table Grape Commission, which also supplied the grape powder, the researchers note that the commission played no role in the study's design, conduct, analysis or preparation of the presentation.
Research on grapes and other fruits containing high levels of antioxidant phytochemicals continues to show promise. U-M will further its research this summer when it begins a clinical trial to test the impact of grape product consumption on heart risk factors.
“Although there's not a particular direct correlation between this study and what humans should do, it's very interesting to postulate that a diet higher in phytochemical-rich fruits, such as grapes, may benefit humans,” Bolling says.
Bolling says that people who want to lower their blood pressure, reduce their risk of diabetes or help with weakened hearts retain as much pumping power as possible should follow some tried-and-true advice to eat a healthy diet low in saturated fat, trans fat and cholesterol, achieve a desirable weight and increase physical activity.
Brown Rice and Angiotensin II
The subaleurone layer of Japanese rice, which is located between the white center of the grain and the brown fibrous outer layer, is rich in oligosaccharides and dietary fibers, making it particularly nutritious. However, when brown rice is polished to make white rice, the subaleurone layer is stripped away and the rice loses some of its nutrients. The subaleurone layer can be preserved in half-milled (Haigamai) rice or incompletely-milled (Kinmemai) rice. These types of rice are popular in Japan because many people there believe they are healthier than white rice.
The Temple team and their colleagues at the Wakayama Medical University Department of Pathology and the Nagaoka National College of Technology Department of Materials Engineering in Japan sought to delve into the mysteries of the subaleurone layer and perhaps make a case for leaving it intact when rice is processed. Because angiotensin II is a perpetrator in such lethal cardiovascular diseases, the team chose to focus on learning whether the subaleurone layer could somehow inhibit the wayward protein before it wreaks havoc.
First, the team removed the subaleurone tissue from Kinmemai rice. Then they separated the tissue's components by exposing the tissue to extractions of various chemicals such as ethanol, methanol and ethyl acetate. The team then observed how the tissue affected cultures of vascular smooth muscle cells. Vascular smooth muscle cells are an integral part of blood vessel walls and are direct victims of high blood pressure and atherosclerosis.
During their analysis, the team found that subaleurone components that were selected by an ethyl acetate extraction inhibited angiotensin II activity in the cultured vascular smooth muscle cells. This suggests that the subaleurone layer of rice offers protection against high blood pressure and atherosclerosis. It could also help explain why fewer people die of cardiovascular disease in Japan, where most people eat at least one rice-based dish per day, than in the U.S., where rice is not a primary component of daily nutrition.
“Our research suggests that there is a potential ingredient in rice that may be a good starting point for looking into preventive medicine for cardiovascular diseases,” said Dr. Eguchi. “We hope to present an additional health benefit of consuming half-milled or brown rice [as opposed to white rice] as part of a regular diet.”