Role of Minerals in Hypertension

Transcription

1 Role of Minerals in Hypertension

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3 Lecture objectives By the end of the lecture students will be able to Define primary and secondary hypertention and their risk factors. Relate role of minerals with hypertention. List the interventions for the management of hypertention. Explain dietary approaches to stop hypertention.

4 Attributable Risk Blood Pressure as a Cardiovascular Risk Overall ½ of heart and stroke* Stroke 60-70%* Heart failure 50% Heart attack 25% Kidney failure 20% Dementia Sexual dysfunction 4

5 Hypertension Definition Hypertension is sustained elevation of BP Systolic blood pressure 140 mm Hg Diastolic blood pressure 90 mm Hg

6 Blood Pressure Classification BP Classification Normal < 120 and SBP mmhg DBP mmhg < 80 Pre-hypertension* or Stage 1 Hypertension or Stage 2 Hypertension > 160 or > 100

7 Classification of Hypertension Primary (Essential) Hypertension - Elevated BP with unknown cause - 90% to 95% of all cases Secondary Hypertension - Elevated BP with a specific cause - 5% to 10% in adults

8 Risk Factors for Primary Hypertension Age (> 55 for men; > 65 for women) Alcohol Cigarette smoking Diabetes mellitus Elevated serum lipids Excess dietary sodium Gender Excessive alcohol intake Stress Heredity

9 Risk Factors for Secondary Hypertension Contraction of aorta Renal disease Endocrine disorders Neurologic disorders

10 Clinical manifestations No specific complains or manifestations other than elevated systolic and/or diastolic BP (Silent Killer ) Morning occipital headache Dizziness Fatigue In severe hypertension blurred vision, vomitting, severe headache

11 Role of minerals in Hypertension

12 Sodium What are sodium and salt? Sodium is a chief extracellular cation About 90 percent of sodium consumed is in form of sodium chloride, table salt Functions: chief role is regulation of fluid balance Necessary for normal nerve and muscle function

13 Dietary Sodium Sources 13

14 Sodium Studies link excess sodium intake to the development of elevated blood pressure, which increases the risk of heart attacks, stroke, and kidney disease.

15 Higher dietary salt increases death from stroke Adapted from Perry IJ et al. J Hum Hypertens. 1992;6:23-25.

16 International scientific and health organizations conclude that high dietary salt: Increases blood pressure Is a health risk WHO/FAO technical report recommends less than 5 g of salt per day Nishida C et al. Public Health Nutr. 2003;7:

17 Potassium Potassium regulates the activity of muscles and nerves. Decrease your chances of developing kidney stones Best sources of Potassium: Avocados Yams Papaya Lentils Dark leafy greens

18 Evidence of Benefits of Potassium on BP A consistent body of evidence from observational studies and clinical trials indicates that high levels of potassium are associated with lower BP. Meta-analyses do reveal a dose response relationship between BP lowering and potassium intake.

19 Calcium Most abundant mineral in body More than 99 percent located in bones and teeth Functions: Helps strengthen bones and teeth Plays a role in muscles, nerves, and blood May reduce risk of kidney stones (dietary calcium)

20 Food sources: Calcium Milk, yogurt cheese, broccoli, calcium fortified soy milk, calcium-fortified juices and cereals

21 Calcium Population studies indicate that high intakes of calcium from the diet are linked with low BP, where as clinical trials using calcium supplements to lower BP have been less compelling. Calcium supplementation has not been shown to prevent an increase in BP or hypertension. The evidence relating calcium and BP reduction is weak.

22 Magnesium Contributes to the relaxation of muscles and nerves. Best sources of Magnesium: Pumpkin & Sunflower seeds Dark leafy greens Salmon Black beans

23 Effect of Magnesium on BP Epidemiologic, observational, and clinical trial data results are inconsistent to indicate that a diet high in magnesium may lower BP. In most epidemiologic studies, an Inverse relationship has been shown between dietary magnesium intake and BP. clinical studies have been less convincing, and the therapeutic value of magnesium in the prevention of hypertension remains unclear.

24 The DASH: (Dietary Approaches to Stop Hypertension)

25 DASH DIET (DIETARY APPROACHES TO STOP HYPERTENSION) Follows heart healthy guidelines to limit saturated fat and cholesterol. Focuses on increasing intake of foods rich in nutrients that are expected to lower blood pressure, mainly minerals (like potassium, calcium, and magnesium), protein, fiber.

26 DASH DIET (DIETARY APPROACHES TO STOP HYPERTENSION) DASH demonstrated that a diet rich in fruit and vegetables and low-fat dairy products with reduced saturated and total fat can result in a clinically significant reduction in BP A subgroup analysis of the DASH trial also found that the BP-lowering effects were more pronounced in hypertensive individuals

27 Lifestyle Modifications Weight reduction Dietary changes (DASH diet: Dietary Approaches to Stop HTN) Sodium restriction Regular physical activity Avoidance of tobacco and alcohol use Stress management

28 Blood pressure is primarily maintained by three systems: Vasopressin (Anti-diuretic Hormone) which controls water balance by regulating the loss and elimination of water into urine. The Renin-Angiotensin-Aldosterone system which regulates the amount of sodium ion (Na + ) lost and eliminated in urine Atrial Natriuretic Peptides (ANP) that counter the actions of Vasopressin and the Renin-Angiotensin- Aldosterone system.

29 What alters blood volume? Removing H 2 O from the body decreases the volume of blood; along with blood pressure. Vasopressin stimulates the kidney distal tubules to recapture the H 2 O in urine passing through the tubules. Sodium ion recovery from urine is stimulated by the Renin-Angiotensin-Aldosterone system which is stimulated by low blood pressure.

30 How are changes in blood pressure detected? Brain, heart, & kidney respond to changes in blood pressure via pressure receptors, baroreceptors, & to changes in ionic composition of blood via osmoreceptors.

31 Aldosterone & Sodium Reabsorption Aldosterone is a steroid hormone, secreted from adrenal cortex Aldosterone regulates both the reabsorption sodium and secretion of potassium in proximal tubule, distal tubule, and collecting duct

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34 Atrial Natriuretic Peptide (ANP) ANP released from the atrium in response to increased atrial stretch via mechanoreceptors. In other words, when plasma volume increases. The effect of ANP are to: 1) Dilate the renal blood vessels to increase the GFR 2) Inhibit the reabsorption of Na + from collecting ducts. 3) Inhibit the release of renin, aldosterone and ADH. The result is to increase the kidney s ability to excrete both water and sodium.

35 The production & role of the ANPs are shown here. These are made by granular cells of the heart atria as a series of peptides that counter the actions of VP & the RAA system. Though natural BP reducers they are not widely employed clinically. Richard E. Klabunde Cardiovascular Physiology Concepts: Atrial and Brain Natriuretic Peptides,

36 Non Pharmacological Treatment of Hypertension DASH diet Regular exercise Loose weight, if obese Reduce salt and high fat diets Avoid harmful habits,smoking,alcohal