Eating more whole-grain bread, rice and oats could be as effective at drugs at reducing the risk of stroke, research by Aberdeen University has found.
Researchers asked 200 people to eat a diet with three portions of whole grains per day or none. A diet high in fibre is known to reduce blood cholesterol and improve digestive health. It was found that the diet rich in wholegrains reduced blood pressure.
Dr Frank Thies, Senior Lecturer at The Rowett Institute of Nutrition and Health University of Aberdeen, who led the study, said: “We observed a decrease in systolic blood pressure 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.
Wholegrains
“This drop in systolic blood pressure could potentially decrease the incidence of heart attack and stroke disease by at least 15pc and 25pc respectively.”
A portion is counted as around 13 to 16g of whole grains, the equivalent of around half a cup of oats or brown rice or a slice of whole-grain bread.
The findings were published in the American Journal of Clinical Nutrition.
Whole grains are cereal grains that contain germ, endosperm, and bran, in contrast to refined grains, which retain only the endosperm. Wholegrains can generally be sprouted while refined grains generally will not sprout. Wholemeal products are made by grinding whole grains in order to make wholegrain flour. Whole grains are a natural source of protein as well as a source of carbohydrates and are made into many different kinds of foods.
Common whole grains include:
* Wheat
* Oat
* Barley – Hulled and Dehulled (not Pearl)
* Maize
* Brown rice
* Farro
* Emmer
* Einkorn
* Rye
* Spelt
* Millet
* Quinoa
* Amaranth
* Triticale
* Teff
* Sprouted Grains
Wholegrains
Common whole grain products include:
* Whole wheat flour
* Whole wheat Bread
* Whole wheat Pasta
* Rolled oats or oat groats
* Triticale flour
* Popcorn
* Teff flour
Common refined-grain products include:
* White rice
* White flour
* White bread
* Hominy
* Pasta (non-wholewheat varieties)
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Early blood pressure treatment is safer and more effective with two medicines than one, a study has shown.
The results are likely to change the way doctors treat the condition, a major risk factor for heart attacks and strokes.
Patients are normally given one drug, with others added, if needed, over a period of months.
But the Accelerate study shows it is best to start treatment with two medicines together at the same time as it can result in much faster and more effective control of blood pressure, with fewer side effects.
Professor Morris Brown, from Cambridge University, who led the trial, said: “The Accelerate study breaks the mould for treating hypertension (high blood pressure). Most patients can now be prescribed a single combination pill and know that they are optimally protected from strokes and heart attacks.”
Professor Bryan Williams, from the British Hypertension Society, said: “This study is important and the findings could change the way we approach the treatment of high blood pressure.”
The research, which involved 1,250 patients with high blood pressure, is published in an early online edition of The Lancet medical journal.
It shows that starting treatment with the two drugs aliskiren and amlodipine in a combination pill produces a 25% better response in patients than conventional “monotherapy”.
The scientists suspect taking the drugs in series allows the body to neutralise each of them in turn. Having them together may prevent this from happening.
Almost 10 million people in the UK are believed to have high blood pressure.
“Eating three portions of wholegrain foods such as porridge every day protects your heart by slashing blood pressure levels,” reported the Daily Express. It said this could be as effective as taking medication.
The study behind this story demonstrates that wholegrain foods give a slight reduction in blood pressure in middle-aged individuals without cardiovascular disease. The study did not assess the effect of porridge itself on health, but compared a diet containing both wholewheat food and oats with a diet high in wholegrain wheat and a diet high in refined grains.
This was a well-conducted randomised controlled trial. Overall, the results support health advice that a diet containing recommended amounts of wholegrains can have a positive effect on blood pressure, which is an important marker of cardiovascular health. This positive effect on blood pressure can be expected to translate into benefits in terms of risk of coronary artery disease and strokes, although this study did not measure such health outcomes.
Where did the story come from?
The study was carried out by researchers from the University of Aberdeen. Funding was provided by the Food Standards Agency and the Scottish Government. Any oat cakes used in the study were provided by Paterson Arran Ltd. The study was published in The American Journal of Clinical Nutrition.
What kind of research was this?
This research assessed how three daily servings of wholegrain foods (either wheat or a mixture of wheat and oats) affected certain markers of cardiovascular disease risk in relatively high-risk individuals.
Evidence has built up over time that eating a diet high in wholegrain foods is associated with a reduced risk of chronic diseases such as diabetes, high blood pressure and coronary artery disease. The evidence is mainly from cohort studies, with one large meta-analysis of cohort studies concluding that three servings of wholegrains a day may protect the heart.
The researchers noted that evidence from a large intervention study was needed, which is why they carried out this randomised controlled trial.
What did the research involve?
Men and women aged between 40 and 65 years from Aberdeen volunteered to take part between September 2005 and December 2008. The participants’ BMIs ranged from 18.5 to 35 (from healthy weight to obese). Of these, the researchers included only people who were either sedentary or moderately active, and who had signs of metabolic syndrome or moderately high blood cholesterol. Those with diagnosed cardiovascular disease, diabetes, high blood pressure or thyroid conditions were excluded. People who habitually ate a lot of wholegrain fibres or took supplements were also excluded. This process resulted in 233 participants for the study.
The participants were randomly allocated to one of three treatment groups for 12 weeks: refined diet, wheat, or oats plus wheat. Apart from these dietary restrictions, the participants were allowed to eat normally. Before they began taking the treatment foods, they were asked to eat only refined cereals and food containing cereals that had been refined and white bread for four weeks) so that everyone was eating the same initially.
The main difference between the three groups was the type of refined cereals and bread being eaten. Those in the refined food group ate only refined cereals and white bread. The wheat group ate only wholemeal bread and wholegrain cereals, while those in the oat and wheat group had a mix of wholewheat foods and oats. Each group ate three servings of the treatment food a day. In total, the recommended servings for the day equalled the amount recommended by the Food Standards Agency for levels of nonstarch polysaccharides (18g/day). The researchers report that the participants were provided with refined, wheat- or oat-based whole grain foods that are widely available in UK shops. They do not specify further which types. Aside from the food that the researchers supplied, the volunteers were able to select their own foods to eat and advice on what to substitute was tailored to individual participant’s diets.
Several measurements, including weight, health, level of exercise, use of medications and anthropometric measures such as blood pressure, arterial stiffness and blood lipids were taken four times during the trial (before the run-in period, and at the start, end and during the trial). The participants kept seven-day food diaries before the study started as well as during the trial. At the end, the authors assessed whether there was an association between the experimental diet and the markers of health that they had measured.
What were the basic results?
In total, 206 participants completed the study and were available for analyses. As expected, at the end of the study, those in the wheat and the wheat plus oats groups were eating more nonstarch polysaccharides. Intakes of vitamin B6 and vitamin D were lower in the wheat plus oats group compared with the refined group, while zinc and magnesium were greater in both wholegrain groups.
After six weeks of their assigned diet, people in the wheat plus oats group had significantly reduced systolic blood pressure compared with the refined group (a reduction of 5mmHg versus 1.3mmHg) and by 12 weeks this improvement was seen in both wholegrain groups. Diastolic blood pressure did not change. There was also significantly reduced pulse pressure in both wholegrain groups (pulse pressure is the numerical difference between systolic and diastolic readings so if systolic readings are going down we would expect pulse pressure to go down too). There were no changes in blood fats except that in the refined food group, ‘bad’ cholesterol (LDL cholesterol) reduced significantly as did total cholesterol. There was no apparent effect of the diet on other markers of cardiovascular health including C-reactive protein, interleukin-6 and markers of insulin problems, including glucose levels.
How did the researchers interpret the results?
The authors conclude that daily consumption of three portions of wholegrain fibre significantly reduces systolic blood pressure and pulse pressure in middle-aged, healthy, overweight men and women. They note that the observed reduction “was similar to” that seen in drug trials and that such levels could reduce the incidence of coronary heart disease and stroke by more than 15% and 25%, respectively.
Conclusion
This was a well-conducted randomised controlled trial, the results of which appear to show that eating wholegrains influences certain markers of cardiovascular health. The findings raise several issues:
* The researchers say this study is the first of its kind to demonstrate a positive effect of wholegrains on blood pressure. They discuss a similar study, the WHOLEheart study, which found beneficial effects in terms of blood lipids and insulin, but which did not find any effect of wholegrains on blood pressure. The researchers discuss the possible reasons for this, suggesting that their study is more robust when it comes to measuring the effects of wholegrain on blood pressure.
* The study measured only indirect outcomes (proxy outcomes) of cardiovascular health. This means that while the researchers claim that the reductions they have seen here equate to the level of effect that would reduce the risk of stroke and cardiovascular disease, this study cannot prove that wholegrains would have such an effect.
* The effect on blood pressure was only on systolic blood pressure, not diastolic. Blood pressure is a measure of the force of your blood in the blood vessels as the heart beats. A blood pressure reading constitutes two measurements: systolic when the heart pumps and the pressure is at its highest and diastolic when the heart relaxes and the pressure is lowest. Both are recorded during a single heartbeat. When interpreting blood pressure both systolic and diastolic levels need to be taken into consideration together, as both are indicators of cardiovascular health. This study noted a small (about 4-5mmHg) improvement in systolic blood pressure with wheat, but the medical benefits of this are difficult to generalise and they are likely to depend on a person’s blood pressure at the start. People in this study did not have high blood pressure. Generally, above 140mmHg systolic and above 90mmHg diastolic is considered to be high. The average systolic blood pressure of participants in this study was around 130mmHg.
While on its own the study cannot prove that wholegrains reduce the risk of stroke and cardiovascular disease, overall, the findings support existing evidence that wholegrains in the diet are important for cardiovascular health. They are recommended as part of a healthy, balanced diet and along with recommended levels of physical activity may help to prevent cardiovascular disease. The study did not compare the effects of whole grains with drugs for blood pressure lowering so any claims that this change to diet achieves the same as drugs do is premature.
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.