Hypertension

1. Hypertension L. Kathleen Maban and Sylvia Escott-Stump:Food, Nutrition & Diet Therapy, 9th 告報者：劉佩姎 營養師 日期：93/03/25

2. Hypertension • Hypertension is the most common public health problem in developed countries. • Called Silent Killer • No cure is available, but prevention and management decrease the incidence of hypertension and disease sequelae.

3. Classification • Essential or Primary hypertension: 90 ~ 95% the cause can’t be determined, therefore treatment is nonspecific. • Secondary hypertension: caused by another disease, ex: renal or endocrine

4. Definition • SBP (systolic blood pressure)  140 mmHg and/or DBP (diastolic blood pressure)  90 mmHg

5. Joint National Committee on Detection, Evaluation, and Treatment of High Blood Pressure

6. Prevalence

7. Morbidity and Mortality

9. Physiology • Blood pressure levels: a function cardiac output mutipied by peripheral resistance (the resistance in blood vessels to the flow of blood) • Diameter of blood vessels • Sympathetic nerve system ( for short-term control) • Kidney (for long-term control)

10. Blood Pressure fail ↓ Sympathetic nerve system ↓ Norepinephrin ↓ Act on small arteries and arterioles ↓ ↑ peripheral resistance ↓ ↑Blood Pressure

11. Angiotensinase Renal retension Vasoconstriction of salt and water Increased arteial pressure Decreased arterial pressure ↓ Renin (Kidney) ↓ Renin substrate Angiotensin I (Plasma protein) Coverting Enzyme (Lung) Angiotensin II (Inactived)

12. Regulatory mechanism falter, hypertension develop. • Neurohormonal and intrarenal • Peripheral resistance↑→ left ventricle of heart increase effort in pumping blood → left ventricular hypertrophy → congestive f=heart failure

13. Primary prevention • A population strategy: lower the blood pressure in general population • A targeted strategy: direct intervention to lower blood pressure at individuals who are at greatest risk of developing hypertension.

15. Genetic predisposition to H/N interacts Obesity Life-style Dietary components

16. Diet-related factors influencing development of hypertension • Changing four modifiable factors has documented efficacy in the primary prevention of hypertension. -Overweight -High salt intake -Alcohol consumption -Physical inactivity

17. Overweight • Two to six times higher in overweight than in normal-weight individuals • Higher prevalence rates are seen in Mexican-Americans and non-Hispanic black women • Greater fluctuation in weight • 50~59 yr non-Hispanic white women • 30~39 yr non-Hispanic black and Mexican-American women • 20~34 yr weight gaining more than 30 lb in a 10 years

18. Factor associated • Low educational attainment • Low socioeconomic status

19. Framingham Study • Increase related weight of 10% was predictive of a 7 mmHg rise in blood pressure

20. Inuslin resistance • hyperinsulinemia • activation of sympathetic nervous and renin-angiotensin system • physical changes in the kidney

21. BMI Energy intake↑ ↓ plasma insulin ↑ ↓ increase renal sodium reabsorption ↓ blood pressure ↑

22. Early identification of children as potential hypertensive

23. Excess consumption of sodium Chloride • Consuming 100 mEq/day or less or sodium was associated with a 2.2 mmHg fall in SBP • The rise in SBP seen with aging over 30 years would be 9 mmHg less and the rise in DBP 4.5 mmHg less if the average sodium intake were lowered by 100 mEq/day

24. Alcohol Consumption • Three drinks per days (a total of 3 oz of alcohol) is the threshold for raising blood pressure and is associated with a 3 mmHg rise Not more than 1 oz of ethanol/day, which is equal to 2oz of 100-proof whiskey, or 24 oz of beer

25. Exercise • Physical activity produces a fall in SBP and DBP of about 6 to 7 mmHg Moderate physical activity defined as 30 to 45 minutes of brisk walking, three to five times per week

26. Other Dietary Factors • Potassium • Calcium • Magnesium • Lipids

27. Potassium • Inversely related • higher potassium intake→lower blood pressure • reduces peripheral vascular resistance by direct arteriolar dilatation, increase loss of water and sodium from the body • Sodium: potassium ratio of the diet is related to BP

28. Clinical trails with potassium supplement yielded mixed results • Dietary potassium is an adjunct to weight control and reduced sodium consumption for prevent of H/N • Na:K ratio of 1.0 is the goal

29. Calcium • African-American and women • Clinical trials showed minimal hypotensive effects of high dietary calcium intake from foods or supplement . • Calcium from dietary sources to meet the RDA is recommended

30. Magnesium • Mg is a potent inhibitor of vascular smooth muscle contraction and may play a role in blood pressure regulation as a vasodilator. • Most clinical studies, Mg supplement has been ineffective in altering blood pressure, possible because of the confounding effects of antihypertensive medications and the short duration of the studies. • Adequate data are lacking to recommend routine supplement with magnesium to prevent hypertension

31. lipids • PUFA Precursors of prostaglandins -affect renal sodium excretion -relax vascular musculature

32. Large doses of fish oils (50 ml daily with 15g -3 PUFA) have lowered BP in mildly hypertensive men Knapp and Fitzgerald, 1989 • Smaller doses (6~20g fish oil/daily) had no effect on BP in hypertensive or normotensive subjects Lofgren, 1993; Sack, 1994

33. Small doses are hazardous with respect to their effect on bleeding time, weight gain, glycemic control and LDL-cholesterol -3 FA is not recommended for preventing hypertension

34. Combination of risk factors for cardiovascular disease • Medication • Management • Life-style modification • Weight management • Salt restriction

35. Medication • Either raise blood pressure or interfere with the effectiveness of antihypertensive drugs, ex: oral contraceptives, steroid, nonsteroidal, anti-inflammatory agent, nasal decongestants, other cold remedies, appetite suppressants, tricyclic antidepressants.

36. Management • Goal: to reduce morbidity and mortality from stroke, hypertension-associated heart disease and renal disease. -increase to at least 50% the number of people with hypertension whose BP is less than 140/90.

37. Life-style modification

38. Life-style modification • Before drug therapy is begun, three to six months of compliant life-style modification should be tried. • Life-style modification can’t completely correct the BP, but they will help increase the efficacy of pharmacological agents and improve other CVD risk factor.

39. Weight management • The effectiveness of weight reduction has been well documented in high in both mild and severe hypertensives. Lower blood pressure Normalize Blood glucose and lipid Synergistic effect with drug therapy • Some stage 1 hypertensive achieve a normal BP by weight loss alone.

40. Once weight is lost, maintenance is critical • High fat intake and a low level of physical activity • Weight maintenance goal: (1)not to gain more than 10 to 15 lb after age of 21 (2)not to have more than a 2 to 3 in. Increase in waist circumference after age 21

41. Salt Restriction • Moderate salt restriction (6g of salt, 100 mEq or 2400 mg Na/day) is recommended for treatment of hypertension. - Normalize Stage 1 hypertension - Enhance drug therapy • Unless congestive hear failure, severe salt restrictions are not necessary.

43. Thanks for your attention