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June-July 2013

Topics:

B vitamins protect brain gray matter
Beet juice lowers blood pressure
Magnesium lowers hypertension
Supplements and macular degeneration
[Practical guidelines are now included at the end of each article]

B vitamins protect brain gray matter

A new study from the University of Oxford in the UK shows that B vitamins can help the brain. With Alzheimer’s disease (AD), gray matter in key areas of the brain atrophies prematurely, leading to cognitive decline. Although there is a familial genetic component to the disease process, non-genetic factors also play a role. For example, a high level of homocysteine in the blood is an independent risk factor for AD (as well as strokes). Certain B vitamins are known to lower homocysteine

In an earlier randomized, controlled study on elderly subjects with increased dementia risk (based on existing mild cognitive impairment), half were given B vitamin supplements and half a placebo for two years. The B vitamins included folic acid (800 mcg), vitamin B6 (pyridoxine, 20 mg), and vitamin B12 (500 mcg). The B vitamins slowed the shrinkage of the whole brain volume over the two-year period.

In this new study, the same researchers used the same B vitamins and found that they decreased atrophy in the gray matter regions specifically associated with the AD process. The shrinkage of the gray matter in the placebo group was seven times higher than in the B-vitamin group. High homocysteine levels at baseline were associated with faster gray matter atrophy, a deleterious effect mostly prevented by B vitamins. The benefit was only seen in patients who had high homocysteine levels (above the median of 11 micromol/L). (Douaud G, et al., Preventing Alzheimer's disease-related gray matter atrophy by B-vitamin treatment. Proc Natl Acad Sci U S A. 2013 Jun 4;110(23):9523-8. doi: 10.1073/pnas.1301816110.)

This of course is a study of the anatomy associated with cognitive decline and eventually to AD, but it is not a clinical study of the actual development of the disease. That will require a longer term study with a focus on the prevention of dementia, but this is certainly suggestive that a few harmless, inexpensive supplements might have a significant effect on AD.

Practical guidelines:

Most multivitamins will contain some folic acid, B6, and B12, but not always in these doses. If you get the supplement through health food stores, they might have these amounts, but not most commercial supplements (for example, Centrum Silver for Men has only 6 mg of B6, 100 mcg of B12, and 300 mcg of folate). I suggest a B-complex or a multi that has at least the study doses, and that you get your homocysteine levels done to be sure you are getting the benefits. Even if your homocysteine level is normal, you will not be harmed by B complex.

Beet juice lowers blood pressure

Nitroglycerin is commonly used to treat angina (chest pain due to coronary artery blockage. Nitric oxide (NO), another nitrate compound, is produced by the lining cells of the arteries (endothelium), the production is enhanced by dietary nitrate, and it is a “relaxant” of the arterial smooth muscle. With relaxation, the vessels open up and the blood pressure drops as a result. Inorganic nitrate is commonly consumed in foods, and it is bio-converted in the digestive tract to nitrite. Nitrite dilates blood vessels and lowers blood pressure.

In a randomized, crossover study, researchers used potassium nitrate supplements (1488 mg of nitrate) versus potassium chloride or beetroot juice (250 ml, containing 341 mg of nitrate), or 250 ml of water (about 8 ounces). In all, 6 subjects were given the potassium nitrate, 20 were given the potassium chloride, and 9 were given the beetroot juice.

Both the capsule nitrate supplements and the dietary ingestion of beetroot juice as a source of nitrate lowered blood pressure in the male subjects, but not in the females. (Kapil V, et al., Inorganic nitrate supplementation lowers blood pressure in humans; role for nitrite-derived NO Hypertension 2010; 56: 274-281.)

A more recent clinical study by the same group showed that eating fruits and vegetables, including beetroot, could lower blood pressure, probably in part because of the nitrates that they contain. (Ghosh SM, et al., Enhanced vasodilator activity of nitrite in hypertension: critical role for erythrocytic xanthine oxidoreductase and translational potential. Hypertension. 2013 May;61(5):1091-102.) They studied 15 untreated hypertensive subjects, and reduced systolic blood pressure by about 12 points.

Practical guidelines:

Eating fruits and vegetables for health benefits is not really questioned by anyone (although some people express reservations about fruits because of the natural sugars they contain; I think this is a misplaced concern). Juicing beets, or any veggies that are commonly put in juice drinks (carrots, for example) is one way to consume more vegetables, but it is probably not as good as eating the whole vegetable due to the loss of the fiber that is present in these foods (as well as whole grains, legumes, and seeds). Fiber is often neglected because it is not nutritive, but it is still very important for bowel cleansing and weight control, and it lowers the risk of diabetes and heart disease. I occasionally juice carrots, apples, beets, and celery as a treat, but you can tell by how sweet the juice is that it should be considered a dessert. When I do, I use the fiber in whole wheat-veggie pancakes so that it does not go to waste.

Magnesium lowers hypertension

Blood levels of magnesium only show a weak correlation to hypertension. This may be due to the regulatory functions of the body that keep magnesium in the blood for more urgent metabolic needs at the expense of other tissues where it might be stored. However, this does not mean that magnesium is not important for maintenance of normal blood pressures. Absorption of magnesium from the diet may be better reflected by urinary excretion of the mineral. This is a more accurate measure of the presence of magnesium in the diet and the ability of the intestines to absorb it.

In a study from the Netherlands, researchers evaluated 5511 participants aged 28 to 75 years who had no hypertension at the start of the study. They followed the subjects for 7.6 years, during which time 1172 participants developed hypertension (blood pressures over 140/90 – their standard, although anything over 120/80 is associated with increased risks). The median urinary magnesium excretion was 3.8mmol/24 hours. (Joosten MM, et al., Urinary magnesium excretion and risk of hypertension: the prevention of renal and vascular end-stage disease study. Hypertension. 2013 Jun;61(6):1161-7.)

Urinary magnesium excretion was inversely associated with the risk of hypertension in a linear fashion (the more magnesium excretion, the lower the risk). This association remained after adjustment for age, sex, body mass index, smoking status, alcohol intake, parental history of hypertension, and urinary excretion of sodium, potassium, and calcium. Each unit increase in magnesium excretion was associated with a 21 percent lower risk. The same investigators found in another study that low magnesium excretion was also associated with an increased risk of ischemic heart disease.

Practical guidelines:

Magnesium is associated with the function of over 300 enzymes. Rich dietary sources include green vegetables (magnesium is what gives chlorophyll its green color), almonds, cashews, soybeans, whole wheat, lentils, brown rice, peanuts, and potatoes. Including these foods in the diet is healthful in a variety of ways. You can also take supplements. I take 200 mg of magnesium aspartate in addition to my healthy diet. Other magnesium compounds, such as citrate and malate, are also good.

Supplements and macular degeneration

Age-related macular degeneration (ARMD) is a deterioration of the sensitive macular region of the retina causing vision loss in the central part of the field of vision, and eventually blindness. It occurs in both dry and wet forms. In the more common dry form, cellular debris is deposited behind the retina and may lead to retinal detachment. In the wet form, which is more severe, blood vessels grow behind the retina, leaking blood and fluid. In the dry form, yellow deposits called drusen are related to elevated cholesterol.

The Age-related Eye Disease Study (AREDS) has been ongoing for a number of years. In April, they released Report No. 35. They enrolled 4757 participants with varying severity of ARMD. They were assigned to either a placebo or the AREDS formulation of antioxidants vitamins C and E, and beta-carotene and/or zinc. Eye examinations were conducted annually with retinal photographs and visual acuity tests. (Chew EY, et al., Long-term effects of vitamins C and E, β-carotene, and zinc on Age-Related Macular Degeneration: AREDS Report No. 35. Ophthalmology. 2013 Apr 10.)

The nutrients included 500 mg of vitamin C, 400 IU of vitamin E, 15 mg of beta-carotene, and 80 mg of zinc. Participants on the active supplement had a 34 to 40 percent lower risk of developing advanced ARMD compared with the placebo group. There was also a 29 percent reduction in the development of moderate vision loss. No adverse effects were associated with the AREDS formulation. In addition, mortality was reduced among the participants assigned to zinc supplements, especially deaths related to circulatory diseases.

Practical guidelines:

The AREDS formula contains modest doses of antioxidants and a large amount of zinc. The zinc appears to be a particularly important component of the formula. When taking vitamin E, I recommend a formula of natural vitamin E (d-alpha tocopherol), as opposed to synthetic (dl-alpha tocopherol). I also recommend a formula that contains significant amounts of gamma-tocopherol, as well as alpha, beta, and delta.

In smokers, beta-carotene supplements of 50,000 IU have been associated with an increased risk of lung cancer. Whether this holds true for former smokers is not clear. The AREDS formula contains 15 mg of beta-carotene, which is equivalent to 25,000 IU. Other carotenoids may be more prudent for smokers, such as lutein, lycopene, and zeaxanthin. However, smoking itself is a significant risk factor for the development of macular degeneration and its progression.

Many healthy multivitamin supplements contain these amounts of vitamins C and E and beta-carotene, but zinc is often lower than 80 mg, so an additional supplement may be needed.

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CONSULTATIONS:

From September to June, I see patients in New Smyrna Beach, Florida.
Call 386-409-7747, or send an email to to make arrangements.

In summer, I have a variable schedule, and I see patients in offices at the
Rothfeld Center for Integrative Medicine in Waltham, Massachusetts. For appointments, send an email to make arrangements, or call: 386-409-7747.

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Information herein is not medical advice or direction. All material in this newsletter is provided for information only. Its contents should not be used to provide medical advice on individual problems. Consult a health care professional for medical or health advice.

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