Abstract
During a meeting of the American Society of Hypertension in New Orleans, LA, in May 2008, an expert panel was convened to discuss nonpharmacologic therapy in hypertension. This is an update of a panel discussion that was held in March 2007. The panel was co‐moderated by Marvin Moser, MD, Clinical Professor of Medicine at Yale University School of Medicine, New Haven, CT, and Mark Houston, MD, Associate Clinical Professor at the Vanderbilt University School of Medicine, Nashville, TN. Panelists included Laura Svetkey, MD, Professor of Medicine at Duke University, Durham, NC, and Brent Egan, Professor of Medicine at the Medical University of South Carolina, Charleston, SC.
DR MOSER:
Mark, do you want to start off and give us your opinion regarding the value of nonpharmacologic therapy in lowering blood pressure (BP)?
DR HOUSTON:
Thank you. I had the pleasure of reviewing the nonpharmacologic therapy of hypertension several years ago. What I determined at that time was that there is a large amount of data on different nonpharmacologic and lifestyle approaches. Unfortunately, most of these data are from short‐term studies with relatively small numbers of patients. Surrogate end points like BP have been looked at, but most of the trials have not been carried out over a long term or have indicated a reduction in target organ damage related to BP lowering.
Some of the studies suggest that BP can be lowered nonpharmacologically to a degree achieved by some of the antihypertensive medications. Clearly, sodium reduction and weight loss are the two most effective nondrug treatments, but there are other things that we should discuss, such as the effects of potassium, magnesium, calcium, nutritional supplements, omega 3 fatty acids, and whey protein on lowering BP.
DR MOSER:
You mentioned that most of the trials of nonpharmacologic therapy were short‐term studies. Many were also very poorly controlled,
DR HOUSTON:
Yes, not only were they poorly controlled but they also had very small numbers of study participants. It is difficult to draw statistical conclusions from the available data.
DR MOSER:
Before we get into specifics, what would you say is your bottom line? Should we continue to recommend nonpharmacologic approaches as initial therapy for all hypertensive patients, or are they a waste of time?
DR HOUSTON:
We should continue to recommend them. We have this assumption, and it is probably correct, that if you get the BP down, it doesn't really matter how you do it. Some benefit will accrue. Having said that, I think we should continue to emphasize this approach as part of an entire program for hypertension therapy.
DR MOSER:
So we're not just wasting our time?
DR HOUSTON:
I don't think so.
DR MOSER:
Okay. Brent, what do you think of the Trials of Hypertension Prevention (TOHP), which was a long‐term trial of nondrug interventions in the management of hypertension?
DR EGAN:
The strength of the study was its length. Interventions such as sodium restriction and weight loss are difficult to maintain over the long term. In many of the short‐term studies, as we know, it is possible to get patients enthusiastic about short‐term adherence, but the long‐term maintenance of any lifestyle change generally proves to be more challenging. TOHP was instructive in that it was able to sustain some changes in terms of possible hypertension prevention.
DR MOSER:
Would you like to give a more specific summary of TOHP?
DR EGAN:
Okay, the initial TOHP and particularly the second phase in which they focused on sodium restriction are of interest. With weight loss and sodium restriction, there was a significant prevention of progression to hypertension, what we now call prehypertension. So I believe that with a relatively intensive intervention, with lots of instruction initially and sustained follow‐up, it is possible to alter the natural history of developing hypertension in people at risk. I think the study is instructive in that regard.
The challenge that remains is how practical such an approach is in everyday practice, because the degree of intervention probably exceeds that which most people would receive in a practice setting.
DR MOSER:
As you mention, TOHP was a carefully controlled study in which sodium retention and weight were monitored carefully.
DR SVETKEY:
I would like to say that I think the efficacy of nonpharmacologic therapy, at least the nonpharmacologic therapies that are recommended in the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7), has been well established. I am referring to weight reduction; the Dietary Approaches to Stop Hypertension (DASH) diet, which is high in fruits and vegetables and low in saturated fat; reduced sodium intake; increased physical activity; and moderation of alcohol intake. Clinical trial data have established their efficacy in lowering BP or preventing hypertension or both (Table I). The issue, of course, is the implementation. The most recent publication of TOHP 2, which was the long‐term follow‐up, is really instructive. In the group that was assigned to the weight loss intervention, the incidence of hypertension years after the study had ended was almost 20% lower than in the control group, despite that the weight loss group had only maintained about 2 kg of weight loss compared with the control group. So even small changes in lifestyle can have important effects.
Table I.
Lifestyle Modifications
| Approximate SBP Reduction, mm Hg (Range) | |
|---|---|
| Weight reduction | 5–20/10 kg of weight loss |
| DASH eating plan | 8–14 |
| Dietary sodium reduction | 2–8 |
| Physical activity | 4–9 |
| Moderation of alcohol | 2–4 consumption |
| Abbreviations: DASH, Dietary Approaches to Stop Hypertension; SBP, systolic blood pressure. Modified from The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure: the JNC 7 report. JAMA. 2003;289:2560–2572. | |
I would agree that we do not have hard outcome data, although there are observational data to suggest that nonpharmacologic interventions affect hard outcomes; as has been noted, any approach that lowers BP should improve outcome. For instance, there was recently a publication of the data from the Nurses' Health Study, that reported that the more closely people followed the DASH diet, the less likely they were to have a cardiovascular event many years later. These are obviously observational data, but I would say again that it is reasonable to assume that if we're effectively lowering BP, there's a very good chance that we're reducing the risk of events. And of course the big challenge is implementation and particularly the maintenance of those behaviors. We are making slow progress in that regard, although that is a very tough nut to crack.
DR MOSER:
We are never going to have a controlled long‐term outcome study because it is impossible to have a nontreated group. So we have to use observational data, and I agree that if you lower the BP, statistical odds are that you are going to influence outcome. How about being more specific about the degree of BP lowering that we might expect from some of the interventions that Laura mentioned? Are the numbers listed in the JNC 7 table realistic? Obviously, we take for granted that nonpharmacologic intervention means weight loss, sodium restriction, moderation of alcohol from 4 or 5 to 1 or 2 drinks a day, and moderate exercise.
DR SVETKEY:
Don't forget that the DASH dietary pattern is also part of the JNC 7 recommendations.
DR MOSER:
Laura, can you be more specific about the DASH diet? How about some numbers?. What if you lost 1 or 2 lb, what if you lost 20 lb, what if you reduced your sodium intake from 3 to 2.5 g/d? In other words, what would happen if people just changed habits without turning their household into a diet kitchen?
DR SVETKEY:
In 3 or 4 separate clinical trials, the DASH diet lowered systolic BP by about ≥6 mm Hg. For other JNC 7 recommendations, there are some meta‐analyses that address that question. With regard to weight loss, it looks like you get a 0.5‐ to 1.0‐mm Hg reduction for every kilogram of weight loss. So that would mean that if you lost about 5 kg (ie, 12 lb) the systolic BP would decrease about by 5 to 10 mm Hg.
With regard to sodium intake, there have also been several meta‐analyses of a large number of clinical trials that suggest that if you reduce your sodium intake to current recommended levels of <2400 mg/d, or about a teaspoon a day, which you can do without buying special products or going crazy with salt restriction, you would decrease systolic BP by somewhere between 2 and 5 mm Hg.
DR MOSER:
Do you have a formula for people to follow when they go into a supermarket?Sodium is now labeled on everything. Do you tell them, for example, if they're on a low‐sodium diet to avoid foods that have 100 or 150 mg of sodium in each portion? Is there a formula that people should follow?
DR SVETKEY:
I tend not to try to give people rules about what they can or cannot eat. Rather, I point out the things that they can do to stay below 2400 mg/d. I have to admit that I'm a little bit of a maverick on the sodium issue. I tell my patients to do the best they can not to add salt at the table; not to put salt in their recipes, or if they have to cook with salt to at least cut the quantity in half; and to avoid very high‐salt foods, like anything that is cooked and preserved for them, frozen dinners, canned soup, or anything that is preserved with sodium. Table II details some high‐sodium foods to limit.
Table II.
Some Foods With a High Sodium Content That Should Be Avoided
| Potato chips | Bouillon |
| Pretzels | Ham |
| Salted crackers | Sausages |
| Biscuits | Frankfurters |
| Pancakes | Smoked meats or fish |
| Fast foods | Sardines |
| Olives | Tomato juice (canned) |
| Pickles | Frozen lima beans |
| Sauerkraut | Frozen peas |
| Soy sauce | Canned spinach |
| Catsup | Canned carrots |
| Many kinds of cheese | Pastries or cakes made from self‐rising mixes |
| Commercially prepared soups or stews | |
| Adapted from Moser M. Clinical Management of Hypertension. 8th Edition. Cado, OK: Professional Communications; 2008. | |
Beyond that, I do not push the sodium reduction for a couple of reasons. One is that it is the one thing that everybody already knows, and two is that when you compare it to the potential for reducing BP, it is much less effective than weight loss or use of the DASH dietary pattern. So if I was prioritizing, I would say that weight loss is the number one priority because it is going to have the biggest impact. The DASH diet is the number two priority, and sodium reduction is number three.
DR MOSER:
Mark, do you agree with that?
DR HOUSTON:
Yes. There's an interesting tribe in South America, the Yanomamo, who consume probably <500 mg of sodium per day and they don't get hypertensive as they get older. In fact, those who make it past the danger of dying from trauma, etc, have BP levels that average about 100/60 mm Hg.
DR MOSER:
Of course, they also burn up lots of calories and are not obese.
DR HOUSTON:
You're right. They exercise a lot, and they're not overweight. So, it's a combination of factors, which is important. We should not just look at the effects of a low sodium intake; we need to understand the importance of an adequate intake of potassium and such minerals as magnesium and calcium. The DASH diet provides a high potassium, calcium, and magnesium intake.
DR SVETKEY:
I want to be clear, I don't in any way doubt that sodium reduction is an important component of BP regulation, and the increase in BP with age may be related to a high sodium intake, especially in so‐called salt‐sensitive individuals. But from a public health and a clinical point of view, I think it's sometimes not useful to emphasize it so much. Most of the salt that people eat in the United States is already in their food, and it is very hard to reduce sodium intake without, as Marvin said, turning your household or your life upside down. So as a practical matter, I tend not to emphasize reducing sodium intake.
With regard to potassium, I think there is good evidence that an increased potassium intake lowers BP. There have been some clinical trials with potassium supplements in which BP has been lowered to some degree, although it seems that when potassium intake is increased with food, it works even better. As suggested, this may have something to do with what else is in foods, magnesium, calcium, or whatever.
The original DASH diet is very high in potassium. We also tested a diet that was pretty much a typical American diet but was increased in fruits and vegetables. It was, therefore, high in potassium but similar to the control diet in other nutrients. This diet did in fact lower BP, but not as much as the DASH diet, which was rich in potassium, calcium, and magnesium, somewhat high in protein, high in fiber, and reduced in total and saturated fat.
DR HOUSTON:
Laura, the data on potassium, as you pointed out, are good. There were several meta‐analyses that suggested that 100 mmol of potassium per day in the diet would result in an average reduction of about 6/4 mm Hg in a non‐hypertensive patient and an even greater reduction in a hypertensive patient, perhaps as much as 8/6 mm Hg. You showed the same thing in the DASH studies, that those who had hypertension had a greater overall BP response than those who were not hypertensive.
DR SVETKEY:
Exactly.
DR MOSER:
Brent, do you agree that the major nonpharmacologic focus for hypertension management should probably still be weight loss?
DR EGAN:
I think that weight loss is extremely useful not only for BP control but obviously for multiple risk factor management (ie, insulin resistance, oxidative stress, and a number of other things).
But I have a few comments on sodium. I think it is important in terms of the BP increase with age. In the INTER SALT study, a large international epidemiological study on the relation of electrolyte excretion and other aspects of lifestyle to BP, I think we have to acknowledge that there are about 4 cultures that drive quite a bit of the relationship between salt and BP. In 1993, there was a Japanese team that went to Nepal and studied two villages there (Kotyang and Bhadrakali). In the population of Kotyang, the body mass indexes over a lifetime average about 18.5 kg/m2. Body fat for the men was less than 10% and for women was 13% or 14%. Of interest, they consume about 200 mmol of sodium per day, as best these investigators could estimate.
DR MOSER:
What is the average body fat content of Americans? Not obese persons.
DR EGAN:
In terms of percentage body fat?I think that for men it would probably be in the range of 15% to 17% and for women up to 20% to 25%. So these folks are very lean and very physically active, with relatively high sodium intakes even by our standards—even in the Southeast. It was observed that these individuals had very little increase in BP with age, and the prevalence of hypertension was extremely low. In fact, the men did not have a detectable increase in BP with age. BP was a bit higher than in the Yanomamo tribe; it stayed at about 110 to 115 mm Hg systolic over the lifetime, but there was virtually no hypertension with aging in this society. I think that what that says is that if we have an extraordinarily healthy lifestyle and stay thin and active, we are able to tolerate a relatively high sodium intake. I think that when other things go wrong, sodium intake is much more of a problem.
One of the things sodium seems to do is exacerbate oxidative stress. I think that animal studies are clear about that. But there are even some human data to suggest adverse effects on nitric oxide and oxidative stress, particularly in people who happen to be salt‐sensitive. So the sodium story is an interesting one and not quite as simple to understand as some would have us believe. Going back a bit to what Laura was talking about, emphasizing diet quality is important. When the diet is high‐quality in terms of potassium, bioflavonoids, and antioxidants, there is a protective effect against some of the sodium that's in the food. There are some interactions there in terms of emphasizing diet quality. It is useful to emphasize this, rather than just emphasizing a single nutrient or element like sodium.
DR MOSER:
I don't think Laura's underestimating the importance of sodium; she is saying that our major effort now should probably be focused on weight and controlling intake of some other minerals. By the way, when you lose weight, you lose sodium.
DR SVETKEY:
I would say that weight and dietary pattern are what matter most.
DR MOSER:
Years ago, we did some studies in the Bahamas, where sodium intake is probably 3 times what it is in the United States, even in the Southeast. Hypertension is extremely common. About 85% of all people older than 60 have significant hypertension, and strokes are a major cause of death. Sodium may not be the only factor responsible for this, but it undoubtedly plays a role.
Most people are aware that sodium restriction is a good idea. And I really do believe that it can be accomplished, as Laura points out, not by dramatically affecting everyday life, but just by avoiding obviously salty foods, not adding salt when cooking, and reading labels.
Now let's follow up on some of the details about other minerals. Years ago, Herb Langford did a study in rural and city residents and found out that young women in rural areas had higher BP values than young women in urban areas. This didn't seem to make sense, given the idea of a more stressful life in cities. One of the reasons he hypothesized was that the girls in rural areas had a high potassium intake, but the potassium intake in urban areas was low, about 30 to 40 mmol/d instead of the average amount Americans consume, which is about 60 to 65 mmol/d. Ideally, as we know, it probably should be about 100 mmol/d.
Laura, let's go back to the DASH diet: high in potassium and magnesium and calcium, high in fiber, and low in saturated fat, all important elements of a so‐called healthy diet. Do you believe that this diet can be implemented in the real world?There is a lot of debate about this. The DASH study, as we have noted, was a feeding study. Many physicians have said that you can't replicate that type of program in the real world; it is too expensive and people won't follow it. You've had a lot of experience with dietary management. Can a DASH‐like diet be implemented?
DR SVETKEY:
Well, let me answer the second question first, with regard to implementation. When we did the feeding study, we created a diet that was a little bit extreme in terms of its nutrient content. Subsequent studies, such as PREMIER and the Weight Loss Maintenance Study, tried to help people implement the DASH dietary pattern. Both of those studies were lifestyle modification studies that implemented the DASH dietary pattern in the “real world.” In both studies, there were significant increases in the nutrients and food groups that we were targeting. So let me review again the nutrient content of DASH.
It is high in potassium, calcium, and magnesium, and it's low in total and saturated fat, with a little more protein than a typical American diet. Fat calories are replaced with complex carbohydrate calories. It was not a low‐sodium diet in its original form, and it was not a weight loss diet in its original form. To achieve these nutrient targets in the lifestyle studies (ie, in the real‐world studies), we encouraged people to eat a lot of fruits and vegetables, on the order of 6 to 12 servings a day. We encouraged them to eat 2 to 3 servings of low‐fat dairy products each day and to reduce their overall meat intake but particularly to reduce the amount of red meats they consumed. In addition, we encouraged them to eat complex grains and some nuts and dried fruits.
In a real‐world setting in the lifestyle intervention trials, when we encouraged people to adopt this DASH dietary pattern but did not provide the food, we saw the intake of fruits and vegetables and low‐fat dairy go up, fat intake go down, and complex carbohydrate consumption go up. Were the same levels that we achieved in the feeding study achieved here? No. But we don't know how much you have to achieve to get the BP‐lowering effect of DASH. We do not know what the dose‐response relationship is with different levels of dietary changes.
We do know that people are able to make dietary changes consistent with DASH and that BP comes down when they do. I think it would be pretty hard for somebody to achieve absolute perfect adherence to the dietary pattern, but we don't know that perfect adherence is necessary.
DR MOSER:
Mark, the DASH diet is an excellent diet. The feeding study demonstrated what might be accomplished under ideal circumstances. What's your take on it? In your experience, can many patients follow it? Or is the DASH diet just a measure of what should be done or should be encouraged? Perhaps a great deal can be accomplished if people achieve only half of the DASH diet changes?
DR HOUSTON:
I believe that if you can just get portions of the DASH diet incorporated into someone's life, you're going to get a benefit. What I typically do in my practice is give a little bit of information to the patient on each visit to avoid overwhelming them. On the first visit, a patient is advised to eliminate anything that's white in the diet. So that means they get rid of most of the starches. Then on the second visit, I tell them to cut out all the sweets and sodas.
DR MOSER:
What if they enjoy pasta as a major part of their diet?
DR HOUSTON:
Whole wheat pasta with fiber would be better. Give advice in stages. Decide what a serving of a fruit and a vegetable really is. A lot of people have no clue. A serving of a fruit or a vegetable is an amount you get in the palm of your hand, which is not a lot, if you think about it. Eight servings a day is not that much if you measure correctly. So I believe that incrementally providing information to the patient to increase adherence does result in long‐term effects. And if you incorporate weight reduction and exercise as part of a program, it will have a beneficial effect.
DR MOSER:
Brent, what do you do?
DR EGAN:
Well, we actually did a small study 4 or 5 years ago in which we instructed a dozen lean, normotensive controls and a dozen obese patients with the metabolic syndrome and prehypertension or stage 1 hypertension on the DASH eating plan. On average, the hypertensive patients were getting 1 fruit and vegetable a day, and we gave credit at that time for French fries, so it was a total of 2 …
DR SVETKEY:
How about catsup?
DR EGAN:
There you go. We should have given credit for that as well. But we did get them to increase from 2 to about 5 servings of fruits and vegetables a day. In terms of low‐fat dairy, initially they were on 1 serving every fifth day. We got them to about 1 serving every 2 or 3 days, and BP decreased by 8/6 mm Hg in the patients with the metabolic syndrome. So it appeared to be significant. We've repeated that more recently for other reasons, and the results again were similar. So we believe that even partial adherence can be quite effective for certain patients, particularly those with elevated BP. We did not look at lean hypertensive patients, but I would anticipate that they would probably benefit as well.
DR MOSER:
So even if you don't follow the DASH diet as originally suggested, it's a very good idea to move toward it.
DR EGAN:
Yes, and it looks as though partial adherence can be quite beneficial.
DR SVETKEY:
Looking at DASH and cardiovascular mortality in the Nurses' Health Study, there appears to be a linear relationship, so that the closer you get to the full dietary plan, the greater the benefit.
DR MOSER:
So it's easy to agree that exercise is good for you, staying lean is good for you, reducing your sodium as much as you can consistent with eating habits is good for you, and following a diet similar to DASH is good for you. Now let's get back to some details about adding various substances to the diet. Is this necessary or useful?There's a lot in the literature, some of it good and some of it bad, about magnesium, calcium, potassium, fermented milk products, and other substances to reduce BP. Do any of these work, Brent? Should we be using supplements if someone isn't ingesting 3, 4, or 5 portions of fruit every day?
DR EGAN:
I believe that if we could identify what an individual might be most deficient in and then replace that, it would make sense. For example, if they are really low in potassium or magnesium, I think giving supplements would be useful.
DR MOSER:
It is very hard to measure magnesium.
DR EGAN:
Yes, it is. In general, the studies with magnesium are equivocal, with a BP lowering of no more than 1 or 2 mm Hg, even in the studies that are positive. What we did more recently was instruct individuals on the DASH eating plan and then have them continue eating their regular diet but take potassium, magnesium, and fiber supplements to match DASH. We attempted to control sodium and calcium so that these cations were not varying. In general, the supplements were not nearly as effective as the DASH eating plan itself. In fact, it was hard to see a statistically significant improvement in BP among the metabolic syndrome patients with potassium, magnesium, and fiber supplementation. There was certainly a tendency toward reduction of BP, but again, the numbers are small—just 15 patients, so I don't want to overinterpret the results. It was fairly clear that the DASH eating plan had a significantly greater BP‐lowering effect than a usual diet supplemented with potassium, magnesium, and fiber to match DASH.
DR MOSER:
So dietary interaction may be more effective than supplements? But there are examples where supplements might be useful; if someone were, for example, on a diuretic, you might want to supplement magnesium?
DR EGAN:
Yes.
DR SVETKEY:
You know, there was a study in patients who had low potassium levels while they were on a diuretic, and supplementing the potassium improved their BP control. You may also recall that the original TOHP, phase 1, compared supplements, I think it was potassium, magnesium, and calcium, and also reduced sodium and achieved weight loss. That's how they got to the second phase, which was just weight loss and sodium restriction, because supplements didn't work.
DR HOUSTON:
I did recently look at the magnesium story a bit. I cannot tell you at this point whether magnesium is or is not beneficial, because the quality of the studies is poor. Different forms and dosages of magnesium were used. Diets were not controlled. Most of the studies didn't use a form of magnesium that is absorbed, so most of it probably was not absorbed. Blood levels were not measured in most studies.
DR MOSER:
Let's talk a little bit more about potassium. We know, for example, that experimentally if you have someone on a high sodium intake and you give them extra potassium, it may negate some of the BP‐raising effects of the sodium. In fact, an increased intake of potassium may prevent the development of hypertension in animals.
What's the ideal potassium intake? We have discussed this before, but perhaps we have to be more specific. Can we achieve it by just having people drink more orange juice and eat bananas and cantaloupe, or do we need supplements?
DR HOUSTON:
I think it's achievable with diet; 60 to 100 mmol/d would be what I would try to achieve in a hypertensive patient. As you know, a banana and a glass of orange juice probably contains close to 25 mmol. If you add some vegetables and fruit, it is probably achievable. Laura, what was the potassium content of the DASH diet?
DR MOSER:
Wasn't the potassium intake about 120 mmol/d?
DR SVETKEY:
Yes, it was 4700 mg/d, or about 120 mmol/d.
DR MOSER:
Actually quite a high intake.
DR HOUSTON:
The other point that Brent was making is that it is important to emphasize the shotgun approach, which is a diet that supplies a large array of micronutrients in smaller doses and then adds single nutrients in high doses as needed in supplement form to really achieve a good BP reduction.
DR EGAN:
We're talking here about the importance of diet quality rather than simply continuing unhealthy diets and adding a supplement to address one of multiple nutritional problems.
DR MOSER:
Brent, do you think that the data on potassium, calcium, or magnesium supplements justify their use for treating or preventing hypertension?
DR EGAN:
I certainly think that for people who are not able to change their dietary patterns and for those with a relatively high sodium intake, particularly in the black or older populations, that the data suggest some beneficial BP effects of potassium supplementation. I think we're all familiar with the work of Lou Tobian that suggests that potassium also protects the vasculature and decreases lipid peroxidation.
DR MOSER:
And decreases stroke.
DR EGAN:
Absolutely. The Health Professionals Follow‐up Study found a strong inverse relationship between potassium intake, including potassium supplements in men taking diuretics, and risk of stroke.
DR SVETKEY:
That had been previously shown in Elizabeth Barrett‐Connors' observational study of older individuals in California, in which stroke risk at the highest potassium levels was much lower when compared with individuals at lower potassium levels.
DR HOUSTON:
Mechanistically, it makes sense because there are data with sodium‐reducing nitric oxide and increasing asymmetric dimethylarginine and potassium actually doing just the opposite. They do kind of balance each other out.
DR MOSER:
Of all the minerals then, if there's a supplement that might play a role in health benefits and lowering BP, it would be potassium rather than calcium, magnesium, or some of the others?
DR SVETKEY:
I would like to say that I think there's really no evidence to support using calcium or magnesium supplements for lowering BP. There have been some meta‐analyses of supplement trials that suggest that they really do not have a significant effect on BP. Even though those nutrients in foods may have an impact, the supplements don't seem to. Whether potassium supplements might be a reasonable approach to treating BP if people aren't able to increase potassium intake with diet, I think, is open to consideration.
DR MOSER:
Brent, any final comments?
DR EGAN:
Well, just a comment that the latest estimates are that we perhaps have 70 to 80 million people with prehypertension, with BP values of 120/80 to 139/89 mm Hg. Those individuals are clearly at risk for transition to hypertension, so I think there is a real need to look at lifestyle approaches that can lower BP and reduce that transition to hypertension. I think some of the things we've discussed today have been proven efficacious in clinical trials. The challenge is to get effectiveness in the community. There is some evidence that a substantial proportion of our patients do adhere to some of these recommendations and receive some of the benefits. I tend to be an optimist anyway, but I think there's potential here. Table III summarizes specific lifestyle changes that impact BP.
Table III.
Lifestyle Modifications for Control of Hypertension and/or Overall Cardiovascular Risk
| • Lose weight if overweighta |
| • Reduce sodium intake to <100 mmol/d (2.4 g of sodium or approximately 6 g of sodium chloride per day)a |
| • Limit alcohol intake to <1 oz/d of ethanol (24 oz of beer, 10 oz of wine, or 2 oz of 80‐proof whiskey; approximately one‐half of these amounts for women and thin persons) |
| • Cease smoking and reduce dietary saturated fat and cholesterol intake for overall cardiovascular health; reducing fat intake also helps reduce caloric intake (important for control of weight and type 2 diabetes) |
| • Maintain adequate dietary potassium, calcium, and magnesium intake |
| • Use relaxation techniques, biofeedback |
| • Consume vegetarian diets, fish oil |
| aThese interventions have been found to be most effective. Data on other interventions are not definitive (see text). Modified from The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure: the JNC 7 report. JAMA. 2003;289:2560–2572. |
DR MOSER:
Mark?
DR HOUSTON:
Just one closing comment. We really didn't discuss the role of exercise, but there are some good data showing that if you achieve 4200 kcal/wk in exercise, you can get about a 10/5 to 12/6 mm Hg reduction in BP once you're conditioned. And. interestingly, there was a dose response up to that level. Once you went over that level, it was actually a flat curve in relationship to reducing cardiovascular events, particularly coronary heart disease and myocardial infarction. Table IV will give you some idea of calories burned with various forms of activity. Low calorie intake is, however, also beneficial.
Table IV.
Caloric Expenditures for Various Activities
| Activity | Approximate No. of Calories Burned per Half Hour |
|---|---|
| Normal activities | |
| Cleaning windows | 130 |
| Gardening | 110 |
| Mowing lawn (power mower) | 125 |
| Sitting/conversing | 40 |
| Vacuuming | 130 |
| Moderate exercise | |
| Bicycling (5 mph) | 105 |
| Bicycling (8 mph) | 165 |
| Bowling | 135 |
| Playing golf (using power cart) | 100 |
| Playing golf (pulling cart) | 135 |
| Playing volleyball | 175 |
| Roller skating | 175 |
| Swimming (0.25 mph) | 150 |
| Walking (1 mph) | 65 |
| Walking (3 mph) | 140 |
| Vigorous exercise | |
| Bicycling (10 mph) | 195 |
| Bicycling (13 mph) | 330 |
| Hill climbing (100 ft/h) | 245 |
| Ice skating (10 mph) | 200 |
| Jogging (5 mph) | 265 |
| Playing squash, handball | 300 |
| Playing tennis | 210 |
| Running (8 mph) | 360 |
| Skiing (10 mph) | 300 |
| Walking (4 mph) | 195 |
| Adapted from Moser M. Clinical Management of Hypertension. 8th Edition. Cado, OK: Professional Communications; 2008. | |
But to summarize what we've discussed, I think the panel has agreed that nonpharmacologic therapy has a definite role; that lowering BP is good no matter how you achieve it; and that the data, except with sodium, the DASH diet, potassium, weight loss, and exercise are not well documented. The numbers of patients are small, and studies are poorly controlled.
DR MOSER:
Laura, any final words?
DR SVETKEY:
I'd just like to add to that summary that I think the real challenge is implementation. We have these recommendations, and we have a clear evidence base for recommending these lifestyle modifications for lowering BP and preventing hypertension. We have in my opinion very little in the way of systems or structures or, frankly, reimbursement for implementing interventions that will help people make these kinds of lifestyle changes. I think that's where the challenge lies right now.
DR MOSER:
Thank you.
Disclosure:
The discussion was supported by Unilever, and each author received an honorarium from Unilever for time and effort spent participating in the discussion and reviewing the transcript for intellectual content before publication. The authors maintained full control of the discussion and the resulting content of this article.