Addressing Hypertension via Nutrition (Stalking a Silent Killer)

Soy is not the only positive protein source when looking at blood pressure regulation. Milk proteins, both casein and whey, are rich sources of peptides that can inhibit vasoconstrictor enzymes such as angiotensin-1-convering enzyme (ACE), and positively impact vasodilation.¹⁰ Researchers from the University of Helsinki, Finland, evaluated the anti-hypertensive mechanisms and vascular effects of tetrapeptides from milk protein in spontaneously hypertensive rats (SHR).¹¹ The tetrapeptides from alpha-lactorphin and beta-lactoglobulin improved vascular relaxation, with the former affecting endothelial function and the latter enhancing endothelium-independent relaxation.

The Finnish researchers also reported long-term intake of the peptides isoleucine-proline-proline (IPP) and valine-proline-proline (VPP) in SHR attenuates the development of hypertension by inhibiting angiotension converting enzyme (ACE), a key regulator for the production of the vasoconstricting hormone Angiotensin 2.12 Further, there is evidence from animal trials that the opioid receptors may be involved in the ability of tetrapeptides to lower diastolic and systolic blood pressure.13

In one clinical trial out of the University of Minnesota, Minneapolis, researchers randomized 30 prehypertensive adults to receive 20 g/d of hydrolyzed whey protein or an unmodified whey control for six weeks.¹⁴ After intervention, the patients taking the whey-derived peptides had significant reductions in systolic and diastolic blood pressure, and improvements in LDL cholesterol and inflammatory markers.

Another beneficial protein source when looking at blood pressure control is fish. Australian researchers recently reported following a dietary pattern with higher consumption of fish, salad and cereals in adolescence positively impacts diastolic blood pressure and sets the stage for preventing chronic disease.¹⁵ In another study from Australia, researchers examined the association between fish consumption and microvascular structure from a 12-year cohort, and found higher consumption of fish had vascular protective effects.¹⁶ And Italian researchers reported hypertensive adults who made a long-term dietary change to consume more fish and vegetables had greater control of blood pressure.¹⁷

A review from the University of Connecticut Health Center, Farmington, noted studies on fish oil and its omega-3 essential fatty acids have shown consuming fish oil can produce a small but significant decline in blood pressure, particularly among adults with hypertension.¹⁸ The International Study of Macro- and Micro-nutrients and Blood Pressure (INTERMAP), an international cross-sectional epidemiologic study of 4,680 adults from population-based samples in China, Japan, the United Kingdom and United States, has looked at the impact of omega-3s on blood pressure parameters.¹⁹ There does appear to be an inverse relationship between total omega-3 intake from food and diastolic and systolic blood pressures, with greater impact related to long-chain omega-3 intake from fish.