Blood Pressure and Vitamin C

What Is High Blood Pressure?

Blood pressure is the force of blood pushing against the walls of the arteries as the heart pumps blood, and, if it stays elevated for a long time, can cause myriad health problems, including heart disease, stroke and kidney failure. Because it has no symptoms, it’s readily ignored. According to the CDC, about one third of Americans have elevated BP. If the first number is higher than 140 and the second is higher than 90, you have high blood pressure. If the first is 160 and the second is 100 or more, you are at stage 2 and really need intervention. It’s true that BP rises with age, but there still are things that can be, and should be, done about it.

There are factors you can control, and factors you can’t. Weight, too much salt, overdoing alcohol, insufficient potassium in the diet, sedentary lifestyle and smoking all are under your authority. Gender, race and family history aren’t. Despite the way it looks, stress can be managed, not always easily, but possible.

What Can I Do About It?

The DASH diet (Dietary Approaches to Stop Hypertension) focuses on very low sodium and high intake of fruits and vegetables, accompanied by a relatively low fat intake that includes lean meats, fish, and nuts and seeds. Being rich in fiber, nutrients and protein, the diet eliminates added sugars, added salt (you have to read labels), and sweets. Total salt consumption for the day shouldn’t exceed a teaspoonful. Because it’ll spike BP, alcohol is limited to two drinks a day for a man, one for a woman (McFarlane, 2007). Information about the DASH plan, either on paper or online, is available free at http://www.nhlbi.nih.gov/health/public/heart/hbp/dash/index.htm.

We realize that the TV remote is a handy gadget. We also realize it put the kibosh on the last vestiges of physical activity for a slew of people. Before remotes were around, many of us used our kids to change channels. Not only high blood pressure, but also other health risks can be eliminated with a regimen of exercise. When you consider the options, exercise isn’t such a bad deal.

Most of us have a heart that is designed to pump blood a certain distance. Forcing it to pump harder and farther is akin to adding a hundred feet to the garden hose and watching it trickle for lack of water pressure. After a while, the heart gets tired of this slavery and goes on strike.  That’s when the trouble starts. Fat needs blood. Every extra pound of fat adds blood vessels.  The more than sixty thousand miles of tubes you already have doesn’t need to be enhanced by the extra miles that grow to feed fat. The bottom line? Lose weight and get your body mass index back where it belongs.

Inhaling a cigarette constricts blood vessels. That’s explains the light high that comes from the first smoke of the day. It reduces oxygen to the brain, just like booze, and you get a brief euphoria. But it can also make blood vessels stiff. Some say that smoking relieves stress.  Maybe so, but physical activity does the same thing and the effect lasts much longer. Plus, you can make new friends with exercise.

Do Supplements Help?

A recent report from Johns Hopkins University says that large doses of vitamin C can lower elevated blood pressure (Juraschek, 2012). The RDA for this vitamin is a mere 90 milligrams, barely enough to provide physiological benefit, but just enough to prevent scurvy. At 500 mg of vitamin C a day for at least eight weeks, subjects experienced a drop in systolic pressure of 3.8 mm Hg and a drop in diastolic pressure of 1.48 mm Hg. For those with existing high BP, the systolic drop was almost 5 mm Hg. Persons taking medication to control their BP could expect a 10 mm decrease. The lead author of this study, Edgar R. Miller, III, M.D., PhD, adds that, although the impact is moderate, it’s sufficient to decrease the number of stroke occurrences.  As is the case with any such investigation, additional study is warranted.

British scrutiny suggests that increased consumption of fruits and vegetables high in vitamin C is the way to go. This study indicated that people with high plasma values of the vitamin (from food) had lower clinical blood pressure. People who supplemented with vitamin C were excluded from this study, so one can only guess at the impact supplementation would have (Myint, 2011). Supplement users might be smiling at this point, or even smirking, but they need to know that combining vitamin C with certain other supplements might just undo what the vitamin can do. Lots of folks open several supplement bottles at one time without knowing of their interactions with each other, with foods, and with medications. This is not a prudent habit.  Many plant polyphenols are beneficial to human health. The timing of their ingestion is important. Australian researchers have found that combining vitamin C with grape seed polyphenols actually raises blood pressure. The hypothesis was that both substances, either alone or in combination, could lower elevated BP.  Vitamin C alone did. Polyphenols alone did not. The combo elevated BP by almost 5 points systolic and nearly 3 points diastolic (Ward, 2005). Need we advise caution and maybe a visit to a functional medicine dietitian or similarly-trained physician? Of course, this is only one study.

Beyond Vitamin C

Citrus fruits and their juices are among people’s favorites. A component of citrus called diosmin, also found in rosemary and used to address venous insufficiency, such as that in varicose veins and hemorrhoids, was found to be an anti-hypertensive agent in lab animals whose blood pressure was artificially elevated with a salt-laced compound. This flavonoid pigment was also found to rectify aberrant blood markers and to be protective of the heart and kidneys (Silambarasan, 2012).

Environmental Insults Raise Blood Pressure

Cadmium is one of the most important environmental pollutants that cause a number of adverse health effects. It’s a major component of tobacco smoke, emissions from steel and zinc production, waste incineration and coal combustion, and might be a fractional element of phosphate fertilizer manufacture (Hutton, 1983). Cadmium’s oxidative potential is witnessed in vascular dysfunction characterized by elevated arterial blood pressure and blunted response to vasoactive agents. Administration of ascorbic acid in a dose-dependent manner normalized blood pressure and improved vascular reactivity while suppressing the formation of oxidized substances (Donpunha, 2011). Lead exposure, whether chronic at low levels or acute at high levels, will elevate blood pressure in humans and animals. Like cadmium, it will generate free radicals and decrease available nitric oxide, the gas that relaxes blood vessels. Irani investigators found that vitamin C is able to prevent lead-induced hypertension (Mohammed, 2010).

Vitamins C is an anti-oxidant nutrient that seems to exert a healthful effect on blood pressure.  That does not leave room for self-treatment, however, because there is no definitive statement about eliminating the cause of hypertension or merely treating it as a symptom. Nonetheless, as adjunct to diet, exercise and lifestyle modification, it’s worth a try. But it isn’t without some pimples. It might reduce the response to warfarin and lower absorption, and might cause a false reading in some blood tests, as in a false increase in creatinine, a false increase in urinary calcium, and a false decrease in urinary sodium. Since vitamin C in large amounts is metabolized to oxalic acid, beware of kidney stones. On the other hand, if you smoke, you need high doses. In that case, get it from food.

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