Olive Leaf and Hypertension

Recently, I found myself leafing through a freebie natural health magazine – if you read this blog, you probably know the type – and came across an article about the use of olive leaf in hypertension. The article was a bit alarmist, and suggested that medical doctors were playing a dangerous game by allowing elevated blood pressure to go untreated. On the contrary, anyone familiar with the creation of ‘prehypertension’ as a diagnostic category or with updates in cholesterol treatment guidelines, knows that when it comes to cardiac risk factors, MDs are nothing if not aggressive. So I walked into the article with a bit of skepticism. However, given that I’d just blogged last week about using magnesium in hypertension, I thought I’d do some investigation into olive leaf and hypertension.

Olive leaf is a little-known herb, but one which has interested me since I read an article stating that it had been shown to inhibit viral reverse transcriptase – one of the enzymes that is crucial to HIV’s ability to infect humans. It’s been variously lauded as an antioxidant, an antimicrobial, and anti-inflammatory. I, however, am primarily interested in its activity as an antihypertensive.

As always, research starts with animal studies. About a decade ago, researchers found that olive leaf extract could reverse hypertension in lab rats who had been made hypertensive through administration of a nitric oxide-synthase inhibitor. While this information is interesting, there exist too many variables to consider this for application to humans – human hypertension arises from a variety of causes and mechanisms, and nitric oxide inhibition is not a common cause – had the rats been hypertensive due to obesity or dietary factors, I would have given the study more consideration, but given the experimental design, it could have easily been inferred that the olive leaf extract merely inhibited the inhibitor, and wouldn’t be useful in humans.

As if noting the limitations of the prior research, a subsequent article addressed this exact question, and found that an extract of olive leaf was effective in preventing severe hypertension in salt-sensitive, insulin-resistant lab rats. This is much more compelling information – these rats have metabolic problems which more closely resemble the ones plaguing Americans, and their hypertension arises from similar causes. This study had me more interested. That said, a more recently published article found that olive leaf extract, when included in the diet of rats fed a high-carbohydrate, high-fat diet, improved a number of markers of cardiac and metabolic markers, including blood lipids, glucose tolerance, and organ changes, but without affecting blood pressure. This study used a model that even more closely mimicked human hypertension, and found no effect on blood pressure. Taken together, these animal studies are interesting, but equivocal.

Eventually, human studies were performed. A 2008 study found that an olive leaf extract did reduce blood pressure in humans, with the greatest changes being a 9 mmHg drop in systolic hypertension, and 4 mmHg drop in diastolic. The study was small, and included only 40 participants, who were assigned to one of three study arms, so this isn’t earth-shattering evidence. Additionally, the evidence only shows a modest reduction in blood pressure, an amount that could be also achieved by diet and lifestyle changes, and the data comes from patients with borderline hypertension, not more severe disease, so it’s hard to tell how useful olive leaf would be in patients with a greater need for aggressive treatment.

The only other human study I was able to find was a 2012 study, which showed that olive leaf extract produced blood pressure decreases of 11.5 mmHg systolic and 4.8 mmHg diastolic in patients with Stage I hypertension. Again, this information does make me pay attention, as it satisfies some of the qualms I had with the earlier study, and the changes in blood pressure are closer to clinically important changes. Even so, there are significant problems with this study, including its being sponsored by makers of the olive leaf extract and a lack of ‘p-values’ or confidence intervals (tools used by researchers as measures of a study’s validity). An interesting study, to be sure, but not the piece of rock-solid evidence that would nail it for olive leaf and hypertension.

The obvious conclusion to all of this is that olive leaf is not yet ready for prime time when it comes to hypertension. The animal studies are intriguing, but the human studies are too small and too unreliable to make clinical judgments on them. Additionally, there is such great number of scientifically-validated ways of reducing blood pressure naturally, that it’s not necessary to turn to something with a less-established track record.

The additional moral to this story is that you can’t always trust what you read in ‘grey’ literature, especially when they are trying to sell you something. Results are overstated and limitations often go unmentioned in these reviews, and without direct access to the studies they are citing, it can be hard to sort out truths. Olive leaf may yet hold promise for the future, but dealing with a chronic condition is never as simple as taking a supplement a couple of times and being done with it – these conditions often require years of work to manage, and the therapeutic benefit of working with a qualified practitioner is crucial to successful outcomes.

How 'Super' Is This Fruit?

Over the past several years, we've been bombarded with hype about 'superfruits' - but what is a 'superfruit', exactly, and are they really better than our native fruits? Is eating an expensive superfruit more beneficial to your health than eating a balanced, vegetable-rich diet? Are they worth the ecological and social cost, as compared with locally-produced fruit and vegetables?

These are all questions I've been asking myself for the past several years, and have been thinking all over again as a result of this recent article in the LA Times on the topic. The article doesn't go into extreme detail, but it's worth a read to get you thinking on a Monday - perhaps the next time you reach for a mangosteen-goji juice, you'll ask if it's really the best option.

Speaking of mangosteens, I'm including this picture to make a point. Only the milky-white interior of the fruit is traditionally edible, yet mangosteen juice is purple - because the indigestible exterior skin has been included. True, the exterior is full of antioxidants (produced to protect the fruit from environmental stresses), but should we really be eating it?

Magnesium and Hypertension

When it comes to calcium and osteoporosis, everyone is agreed – NDs, MDs, acupuncturists, NPs, and chiropractors all recommend 1200 mg of calcium a day to help ward off the onset of osteoporosis. By contrast, there’s not as much discussion of magnesium when it comes to high blood pressure, despite an overwhelming amount of research into the topic, a fact at least partly explainable by inconsistent results in clinical studies. This week, I’m going to write on this topic, referencing select articles from the medical literature – there are thousands of articles on the topic of magnesium and hypertension, and it’s easy to get lost in the sea of literature.

Let me start by discussing briefly the epidemiological information on the topic. I won’t present studies here, though there are many, but in general, the research indicates that people who consume higher amounts of magnesium have, in general, a lower prevalence of hypertension, lower blood pressure in general, and lower incidence of stroke. Of course there are studies that have found no association, as is the case when you have enough studies devoted to a given topic, but a greater number of studies indicate that there is a relationship present, and the evidence is quite compelling.

One of the reasons that I’m inclined to believe the link is because there exist plausible mechanisms for magnesium’s ability to reduce blood pressure. A recent article published in the Journal of Clinical Hypertension elaborates on the biochemistry behind magnesium’s role in hypertension, indicating multiple pathways by which it acts to lower blood pressure, but primarily likening its action to that of a calcium channel blocker (a class of medication used for hypertension and chronic heart failure). Much like a calcium channel blocker, magnesium induces vasodilatation of arteries and regulates cardiac contractility, thus lowering blood pressure and improving the function of the heart. It’s also been suggested that the role that magnesium plays in reducing blood pressure is in part due to the action its presence exerts on other minerals in the body, including sodium, potassium and calcium.

As always, none of this should be taken without evidence that it actually lowers blood pressure in a clinical setting. A 2002 meta-analysis, which looked at 22 trials, including 1220 patients, found that magnesium provided mild benefit to hypertensive patients, although this benefit was dose-dependent, which suggests that greater benefit might be derived from higher doses of magnesium. Since then, further studies have been published that indicate benefit, albeit mild, from magnesium supplementation (1, 2). Taken together, these studies indicate that there is some benefit to be had from magnesium in regards to hypertension. However, all authors more or less agree that the benefit is somewhat inconsistent in clinical trials. The authors of the previously mentioned meta-analysis indicated that small studies and variable study design was a likely factor in the inconsistencies, and called for larger studies in order to more clearly define the benefit and role of magnesium in hypertension.

One piece of the puzzle that has as yet not been fully fleshed out, but which I believe is likely to answer many questions is that of magnesium deficiency. As early as 1983, a study published in the British Medical Journal showed that magnesium could reduce blood pressure significantly, and postulated that it was due to a correction of magnesium deficiency. However, this hasn’t been a major area of research in the intervening period, although a recent study showed that magnesium did produce surprisingly large decreases in blood pressure among a collection of hypertensive diabetics who also had low serum magnesium. This piece of information may give us clinical guidelines regarding when to prescribe magnesium for hypertension, and when to resort to other measures. There’s been some dispute in the past as to the best way to measure a patient’s magnesium status, but I think the clinical correlation here points the way forward.

So what’s the take home message? In all, magnesium does appear to provide some mild benefit in cases of hypertension, a benefit even more marked if the patient is demonstrably low in magnesium. As always, be in consultation with a healthcare provider about using nutritional supplements to help combat disease, especially one with consequences as serious as hypertension – additionally, magnesium is not without side effects, and it takes an experienced provider to help guide you through that.

A Graphic to Explain Snacking

It's Monday again. How about a good, old-fashioned graphic?

This one gives some information about understanding how a food's glycemic index influences whether or not it's a good snack choice. Unfortunately, they don't include nuts or seeds (my favorite snack foods), but this is still a great tool. Many thanks to the people at Massive Health for putting this together.

Is It Really Allergy Season Again?

Last year, I wrote a comprehensive blog entry about allergies in response to a friend's inquiries. If you're suffering from allergies this year, I suggest you click this link to get back to that article - it's extensive and discusses a variety of natural approaches to allergy treatment. This year, I'm going to discuss two more factors in treating seasonal allergies, one is a treatment and the other is a clinical pearl.

In my many years of working in natural health, not only in clinical practice, but in my time at a health food store, I have often heard patients say that they consume local honey during the allergy season in order to prevent the allergic symptoms. In theory, it would seem to make sense – consuming small amounts of allergen desensitizes the immune system to the offending allergen, so that the body doesn’t react as strongly. This is, after all, roughly how allergy shots are believed to work.

But what does the research say? In our modern world, we like to see the hard data and don’t necessarily believe everything we hear, no matter how plausible it may seem.

I was able to find only two articles on the topic of honey consumption to reduce allergic symptoms. The first, conducted in 2002, allotted 36 participants to receive either a local, unfiltered honey, a mass-produced commercial honey, or a honey-flavored corn syrup placebo – participants consumed one tablespoon per day, and reported their symptoms to researchers. The results were poor, and researchers concluded that local honey provided essentially no benefit. However, the study had significant limitations, and I’m not sure we can take this result as completely valid. A third of participants dropped out of the study because they didn’t like the taste of the honey, reducing the study’s size to only 23 participants. A group that small is very unlikely to produce statistically significant results, not to mention the fact that small groups may not represent the larger population. The study design, with three arms, each receiving a different type of ‘honey’, was ingenious, and it would be great to see this repeated using a larger group. (Interestingly, the drop out rate was highest in the corn-syrup placebo group, and lowest in the local honey group – perhaps because local honey tastes better?)

The second study assessed the ability of honey to reduce allergic symptoms among participants who suffered birch pollen allergies. This study also featured three arms – one consuming honey with birch pollen added, one consuming regular honey, and a control group using their usual allergy medication. The results here were stronger – the group was still fairly small at 50 participants, but the drop out rate was much lower. Researchers found that participants consuming honey had lower total allergic symptoms, more asymptomatic days, fewer severe days and less antihistamine use, indicating a significant benefit to honey consumption. No significant differences were found between the group consuming normal honey and honey with birch pollen, however, which makes us question the exact mechanism behind honey’s effect on seasonal allergies. Here’s the caveat – the honey-consuming participants started consuming the honey in November in order to reduce their springtime allergies, so if you’ve not yet started your honey consumption, you may have to wait until next year to try this out.

Taken together, these studies present a mixed view of honey and seasonal allergies. Honey has a number of additional benefits, and few would fault you for consuming local honey, but the science is mixed. Hopefully we’ll see more studies on this topic in the future.

So here’s part two – the clinical pearl.

Just a few days ago, a patient came to me asking about allergy prevention. I conducted an intake, as per my usual, and as it seemed she was suffering from seasonal allergies, as she did every year, I made recommendations along the lines of what I wrote about last year. This week, I heard back from her, and found out that she hadn’t gotten any relief from the supplement I’d recommended – in fact, she had gotten significantly worse!

Far from her sniffling, sneezing and watery eyes, a day or two after I saw her, she’d developed pain and some really thick mucus discharge – unable to reach me, she’d gone to her family doctor on short notice. It turns out that she’d developed a sinus infection in the day or two after I saw her. She’s on antibiotics now, and we’ll see how she fares. The important lesson is this – complementary therapies are extremely effective, but only for those conditions for which they are indicated! Always make sure you make a proper diagnosis before proceeding on to treatment. I was a bit unlucky because she’d not fully developed the sinus infection when I saw her, but the incident underlined for me the importance of not missing the diagnosis!

That’s all for this week, allergy sufferers. Here’s hoping you find some relief!

A Kefta Recipe

Made all over the Middle East and called by a variety of names, kefta are lightly spiced, aromatic lamb meat balls, and are a guaranteed hit with any audience (even the most lamb-resistant). Traditionally, kefta are grilled, but as many of us apartment-dwellers don't have access to grills, the following recipe has been adapted for an oven.

2 lbs ground lamb
1 medium onion, chopped
3-4 tbsp flat-leaf parsley
3-4 tbsp cilantro
1/4 tsp cumin
1/4 tsp coriander
1/4 tsp ginger
1/4 tsp cinnamon
1/2 tsp salt
1/4 tsp pepper
1/4 tsp dried red chili powder (I use chipotle, but cayenne is also acceptable)

Combine all ingredients except the lamb in a food processor and puree. The result should be very green and relatively thick.

Combine the vegetable and spice mixture with the lamb in a large bowl. I find that in order to get a consistent mixture, you need to mix by hand, which of course gets your hands very, very lamb-y. When you've mixed them fully, roll them into small meatballs about the size of a walnut. Evenly space them on a cookie sheet or in a baking dish.

Place in preheated oven and cook at 400 for 20-25 minutes, until meatballs attain a pleasant firmness. Finish under the broiler for about 5 minutes, or until the meatballs are lightly browned.

Though not a traditional topping for kefta, I find that they go very well with muhammara. The contrast of the sweet meat and light spices with the tang of the pomegranate is a guaranteed crowd-pleaser.

Three Things You Didn’t Know About Menopause

I spend a significant amount of time every week reading medical research abstracts. Most of what you come across while doing that is fairly typical, especially if you’re a naturopathic physician concerned with diet and exercise – study after study will show that regular exercise, not smoking, and a healthy diet prevents a large number of diseases and symptoms. Of course, each study examines a slightly different aspect of a healthy lifestyle, with one looking at omega-3 fats, another at fiber, and a third at moderate physical exercise, but in total, they more or less reinforce each other.

Occasionally, however, you come across really unexpected information, the sort of stuff that makes you stand up and say, ‘What?!’ Today’s column is devoted to three such articles relating to menopause.

The first is about night sweats. In a study of 867 women conducted over 11.5 years, it was discovered that women who had both hot flashes and night sweats had a 30% lower risk of all-cause mortality than women who did not have this combination of symptoms. Women who had hot flashes alone did not have this benefit. Adding further interest to the finding is the fact that women who had night sweats but not hot flashes had a similar protective benefit, though in this case it extended only to cardiovascular disease and coronary heart disease. The researchers controlled rigorously for a variety of risk factors, including hormonal therapy, further strengthening the finding.

The main question to ask ourselves with this study is – why could this possibly be happening? The causes of vasomotor symptoms associated with menopause are poorly understood, so we can really only speculate as to why night sweats apparently provide a protective benefit. I’ll be on the lookout for more info on this.

The second is about hot flashes. A team of Greek researchers found that women with increased subclinical atherosclerosis suffered from more severe hot flashes. You lay people are probably wondering what this means – here’s a brief explanation: researchers measured the amount of plaque in the carotid arteries of 110 women via ultrasound, and discovered that those women who suffered more severe hot flashes also had thicker deposits of plaque in their artery walls. Carotid artery plaque is routinely used as marker for atherosclerosis throughout the body. The increases in plaque were minor, and the study population was somewhat small, but the findings were statistically significant, and appeared to correlate to the severity of the symptoms – the women were classified as having no symptoms, minor symptoms, or moderate to severe symptoms, and it was clear that progressively severe symptoms were correlated to progressively severe plaquing.

Here again, because menopausal symptoms are so poorly understood, we can only guess at why atherosclerosis might play a role in their prevalence. What’s interesting though, is that hot flashes may help to alert clinicians to cardiovascular risk in the future.

Finally, severity of menopausal symptoms may be largely influenced by the time of year in which you were born. I’ll admit that this research left me astounded. A group of Italian researchers found that menopausal symptoms are significantly more severe in women born during the spring and summer, as opposed to women born the fall. Not only was this finding statistically significant, but the effect was also remarkably strong – the women born in the spring and summer had symptom scores that were more than twice as high as their counterparts born in the fall. This applied more strongly to symptoms of anxiety and depression, but also quite strongly to somatic symptoms as well.

Despite reading a lot of research, this really counts as one of the most surprising studies I’ve seen. I was tempted initially to dismiss the findings, but this study was done on quite a large group of women – over 2500 – and once you get groups that large, the chance of having fluke results diminishes. The clinical significance of this result has yet to be borne out, but for the time being, this is a fascinating result to read about.