Do you have hypertension or high blood pressure? They are one in the same, with hypertension being the formal, medical term for high blood pressure, which is defined as having a blood reading of 140/90 or higher (prehypertension is 120/80 to 139/89).
High blood pressure accounts for 62 percent of all strokes, 49 percent of all ischemic heart disease (reduced blood supply to the heart), and 13 percent of all-cause mortality worldwide. In short, it is a serious health threat.
As such, researchers have spent years, decades really, and millions upon millions of dollars looking at causes and treatments for high blood pressure. While the majority of studies (and money) focus on pharmaceutical drugs, several have looked at lifestyle choices, such as stress and diet.
It is the dietary studies on lowering high blood pressure naturally that caught the attention of several researchers from Beijing. With all of the differing dietary studies for hypertension, they culled together research on 27 different dietary factors affecting blood pressure, the research associated with those factors, and the various recommendations from around the globe. And what they found was pretty interesting.
Dietary Concerns Associated With High Blood Pressure
Of the 27 factors they studied, the ones that stood out included:
- Fish oil
- Body weight
- Combination diets
Of these, sodium had the most definitive research behind it, showing that high sodium intake was a serious risk factor for high blood pressure. They point to several studies supporting this conclusion. One in particular, a meta-analysis of 13 observational studies that included more than 175,000 participants, found “high salt intake was independently associated with increased risk of stroke and cardiovascular disease.”
They then point to a report from the World Health Organization (WHO), which acknowledges a direct relationship between salt and blood pressure. The report indicates that reducing salt intake from 10 grams per day to 5 grams would reduce stroke rates by 23 percent and cardiovascular disease by 17 percent.
Potassium is slightly more complicated. While most of the research supports the idea of potassium being good for lowering blood pressure, the form and amount vary wildly. The American Heart Association’s recommendations suggest 4.7 grams of potassium a day. In Latin America, the recommendation is for more than 6 grams of potassium a day.
Australia, Canada and China all recommend increasing your intake of fruits and vegetables that are high in potassium. However, the guidelines for the Canadian Hypertension Education Program, the British Hypertension Society, and the National Institute of Health and Clinical Excellence of the United Kingdom recommend NOT taking potassium supplements.
And, to make matters more confusing, researchers pointed to a meta-analysis of 33 randomized controlled trials in which participants either took potassium chloride supplements or increased their intake of potassium-rich foods. The analysis found that those who had increased levels of potassium had average reductions in both systolic blood pressure (4.44 mmHg) and diastolic blood pressure (2.45 mmHg).
Researchers believe that part of the reason for the discrepancies in potassium recommendations has to do with a lack of large, well-designed studies.
On the fish oil front, the research is clear, but the recommendations are not. For example, a 1993 meta-analysis of six studies with nearly 300 hypertensive participants found that taking fish oil (an average of 6.7 grams daily) reduced systolic blood pressure by 5.5 mmHg and diastolic blood pressure by 3.5 mmHg. A second meta-analysis confirmed this. In that study, 31 trials with more than 1,300 participants found that those taking fish oil daily (average of 4.8 grams) reduced systolic blood pressure by 3 mmHg and diastolic blood pressure by 1.5 mmHg.
Sounds good, right? But only Japan recommends taking fish oil supplements for blood pressure. Additionally, only Japan, Australia, China, South Africa, and the European Societies for Hypertension and Cardiology recommend increasing your intake of fish for blood pressure. Researchers suspect that, despite the positive research, the taste of fish and/or fish oil supplements, as well as possible issues with belching and diarrhea related to fish oil supplements, may be part of the reason that supplementation is not more strongly encouraged.
So let’s look at something many people do like: alcohol. Unfortunately, there is consistent evidence that excessive alcohol intake increases your risk of high blood pressure. One meta-analysis of 12 studies found that when daily alcohol intake was more than 50 grams (less than two ounces), a man’s risk of high blood pressure increased by 57 percent and a woman’s increased by 81 percent. Increase daily intake to 100 grams (about 3.5 ounces), and risk climbed to 147 percent in men and 181 percent in women.
That means that one vodka tonic made with two ounces (or shots) of booze increases your risk. Just one. Yet, no one, not even the American Diabetic Association, will come out officially against alcohol and its associated risk with high blood pressure.
When it comes to combination diets, the DASH plan (dietary approaches to stop hypertension) is the most widely accepted. The United States, Canada, Japan and the U.K. all recommend the DASH plan for reducing and managing high blood pressure. This program features fruits and vegetables, low-fat dairy, and low sodium and saturated fat intake. Interestingly, with the exception of Japan, Asia does not endorse the DASH plan.
Lastly, when it comes to body weight, there seems to be consistent consensus that being overweight or obese is associated with increased risk of high blood pressure. Therefore, the recommendation from nearly every country examined is to maintain a BMI of 25 or less to reduce your risk of hypertension.
Distilling the Information
After culling through all of the studies, findings and conclusions from nearly 10 different countries, researchers concluded, “An obvious need exists for improvement, development, and standardization of the methodology of studies addressing dietary factors and hypertension.”
They point to the WHO global strategy as the best overall recommendations for reducing your risk for high blood pressure. This includes:
- Physical exercise
- DASH plan
- Salt reduction
Taking the research detailed here, we would take this one step further and suggest the following:
1. Keep daily sodium intake to 5 grams or less (about one teaspoon).
2. Increase intake of potassium-rich foods.
3. Increase intake of wild-caught fish and, ideally, supplement with at least five grams of fish oil daily.
4. Keep your BMI below 25.
5. Follow the DASH dietary plan.
6. Keep alcohol consumption to no more than two or three drinks a week. Make it a treat, not a habit.
And, remember, it is never too late to embark on healthier lifestyle choices. The human body demonstrates a remarkable willingness to heal if provided with the right inputs.
 The World Health Report 2002: Reducing risk, promoting healthy life. WHO [online].
 Zhao, D et al. Dietary factors associated with hypertension. Nat Rev Cardiol. 2011 July 5. [Epub ahead of print.]
 Strazzullo, P et al. Salt intake, stroke, and cardiovascular disease: meta-analysis of prospective studies. BMJ 2009;339, b4567.
 Creating an enabling environment for population-based salt reduction strategies: report of a joint technical meeting. WHO 2010 [online].
 Whelton, PK et al. Effects of oral potassium on blood pressure. Meta-analysis of randomized controlled clinical trials. JAMA. 1997;277:1624-32.
 Appel, LJ et al. Does supplementation of diet with “fish oil” reduce blood pressure? A meta-analysis of controlled clinical trials. Arch Intern Med. 1993;153:1429-38.
 Morris, MD et al. Does fish oil lower blood pressure? A meta-analysis of controlled trials. Circulation. 1993;88:523-33.
 Taylor, B et al. Alcohol and hypertension: gender differences in dose-response relationships determined through systemic review and meta-analysis. Addiction. 2009;104:1,981-90.