Beets Lower Blood Pressure
Study: Kapil V, Khambata RS, Robertson A, Caulfield MJ, Ahluwalia A. Dietary Nitrate Provides Sustained Blood Pressure Lowering in Hypertensive Patients: A Randomized, Phase 2, Double-Blind, Placebo-Controlled Study. Hypertension 2014.
We know that nitric oxide (NO) causes vasodilation and can lower blood pressure. Supplements (L-arginine) and pharmaceuticals (nitroglycerin) that raise NO have not worked well in part due to tachyphylaxis. An example of tachyphylaxis is caffeine and headaches. Initially caffeine treats a headache but then it can cause rebound headache when the vasoconstriction results in rebound vasodilation. Beetroot juice appears to have a long half-life, preventing tachyphylaxis with a sustained blood pressure lowering effect.
Nitrate Physiology
See figure below. Nitrates (NO-3) get reduced to Nitrites (NO-2) through enteral bacteria that produce high amounts of nitrites in the salivary glands that are swallowed and then reabsorbed in the intestines and excreted in the stool (the reason manure is such a good fertilizer, rich in nitrites). Nitrites get further reduced in the endothelium to nitric oxide (NO).
Do the nitrates in processed meat do the same thing?
Baloney, hot dogs, salami, etc. are treated with sodium nitrate and nitrite to preserve the meat and maintain its pink color. Otherwise these meats would look like your cadaver from medical school. One of meat’s main amino acids is amine. This combines with nitrate to form nitrosamines which in high amounts can increase the risk of cancer. Vegetables include anti-oxidants that keep the nitrosamines in check. Processed meat is also high in sodium and saturated fat which add to the health concerns with high consumption.
The Effect on Blood Pressure
Twenty-four hour blood pressure monitoring showed a sustained reduction of 7.7 mmHg systolic and 5.2 mmHg diastolic with 250 ml of beetroot juice once daily (6.4 mmol nitrate) when compared to placebo which was a nitrate-free beetroot juice. This is just slightly less than the average blood pressure drop with single anti-hypertensive drug therapy (9.1 mmHg/5.5 mmHg). The nitrate rich beetroot juice also improved endothelial function by ~20%.
Which Vegetables have the most Nitrates?
Any root vegetable (soil is rich in nitrates) such as beets, carrots or turnips. Dark greens including spinach and lighter green celery and leaks are also good sources. This should not be a surprise as the DASH diet1 and Mediterranean Diet2 are rich in these foods and have been found to trump most every pharmaceutical we prescribe for overall health effects.
Side effects
Turning the urine and stool red was the main side effect. Those with a history of oxalate urinary tract stones should be cautious as excessive nitrates could increase the risk of recurrence. And theoretically, high nitrate intake could increase the risk of headaches due to vasodilation. This was not seen in this study.
Conflict of Interest: A senior author on this study is the director of Heartbeet, LTD.
References
1.Smith PJ, Blumenthal JA, Babyak MA, Craighead L, Welsh-Bohmer KA, Browndyke JN, Strauman TA and Sherwood A. Effects of the dietary approaches to stop hypertension diet, exercise, and caloric restriction on neurocognition in overweight adults with high blood pressure. Hypertension. 2010;55:1331-8.
2.Estruch R, Ros E, Salas-Salvado J, Covas MI, Pharm D, Corella D, Aros F, Gomez-Gracia E, Ruiz-Gutierrez V, Fiol M, Lapetra J, Lamuela-Raventos RM, Serra-Majem L, Pinto X, Basora J, Munoz MA, Sorli JV, Martinez JA, Martinez-Gonzalez MA and the PSI. Primary Prevention of Cardiovascular Disease with a Mediterranean Diet. N Engl J Med. 2013.