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Advanced Nutrition Diet and Arterial Hypertension MargiAnne Isaia, MD MPH DIET AND HYPERTENSION SYSTEMIC HYPERTENSION Definition Systolic BP ≥ 140 mm Hg & Diastolic BP ≥ 90 mm Hg Taking antihypertensive medications Prevalence approx 18% of adults and 50-70% of elderly (>65) population or BP ≥ 130/80 mm Hg in patients with Diabetes, Chronic Kidney Disease, Coronary Artery Disease or BP ≥ 120/80 mm Hg in patients with Heart Failure Types Essential hypertension (idiopathic, primary) 95% of cases both systolic and diastolic pressure are elevated Isolated systolic hypertension only systolic pressure is elevated 2/3 of elderly population with hypertension consequence of age-related sclerosis of large capacitance arteries responds to sodium restriction and diuretics DIET AND HYPERTENSION JNC7* Classification of BP for adults aged 18 years and older BP Classification Systolic BP mm Hg Diastolic BP mm Hg Lifestyle Modification Normal < 120 ≤ 80 Encourage Prehypertension 120-139 or 80-89 Yes Stage 1 Hypertension Stage 2 Hypertension 140-159 or 90-99 Yes ≥ 160 or ≥ 100 Yes and JNC7* Joint National Committee on Prevention, Detection, Evaluation and Treatment of High BP In addition to classifying stages of HTN on the basis of average BP levels, clinicians should specify presence or absence of target organ disease and additional risk factors (this information is useful for risk assessment and treatment) DIET AND HYPERTENSION CARDIOVASCULAR RISK FACTORS/TARGET ORGAN DAMAGE Major risk factors Hypertension Age (older than 55 for men, 65 for women) Diabetes Mellitus Elevated LDL-C Low HDL-C Glomerular Filtration Rate less than 60 ml/min Microalbuminuria Family history of premature heart disease (M < 55, F < 65) Obesity ( BMI ≥ 30 kg/m2 , Waist Circumference M > 40 inches, F >35 inches Physical inactivity Smoking Target organ damage Heart Brain Left Ventricular Hypertrophy Angina/prior Myocardial Infarction Prior coronary revascularization Heart Failure Stroke or transient ischemic attack Dementia Chronic Kidney Disease Peripheral Arterial Disease Retinopathy DIET AND HYPERTENSION DETERMINANTS OF BLOOD PRESSURE Arterial pressure is determined by - cardiac output amount of blood pumped by heart (vol/min) = = stroke volume x heart rate Stroke volume cardiac contractility vascular volume Heart rate - peripheral vascular resistance - structural and functional changes in the vasculature affect vascular resistance - increased vascular resistance induces structural and functional changes Vascular resistance is determined by - viscosity of blood - width of vessels (constriction or dilation) controlled by muscle tone in vessel wall DIET AND HYPERTENSION PRIMARY HYPERTENSION Determinant Factors: Sympathetic nervous system hyperactivity tachycardia and elevated cardiac output Abnormal cardiovascular or renal development abnormal development of aortic elasticity or reduced development of the micro vascular network Renin-Angiotensin system activity plasma Renin levels are classified in relation to dietary Na intake or urinary Na excretion Angiotensin II = potent vasoconstrictor and major stimulant of Aldosterone release from adrenal gland Defect in natriuresis normal individuals increase Na excretion in response to increased arterial pressure Intracellular Sodium and Calcium Na elevated in the cell may lead to increased intracellular Ca this may explain the increase in vascular smooth muscle tone characteristic of established hypertension DIET AND HYPERTENSION REGULATION OF BLOOD PRESSURE Sympathetic nervous system – responds immediately baroreceptors monitor blood pressure - vasomotor center in the brain - SNS innervated tissues contract or dilate vascular bed Renin-angiotensin system – retains Na and H2O to increase blood volume - constricts blood vessels - increases Aldosterone release Kidneys- respond to renin-angiotensin system Aldosterone and Antidiuretic hormone (ADH) involved Homeostatic control of blood pressure Short term: SNS, vasoconstriction, vasodilatation Long term: fluid volume, RAA system DIET AND HYPERTENSION RISK FACTORS FOR HYPERTENSION Identified by Epidemiology Risk factors: - Smoking - Dyslipidemia - Alcoholism - Diabetes Mellitus - Obesity - Sedentary lifestyle - Diet low in K and high in Na DIET AND HYPERTENSION EXCESS SODIUM INTAKE AND SYSTEMIC HYPERTENSION Epidemiological data Primitive people who eat little or no Na have low incidence of HTN and their BP does not rise with age Yanomamo Indians of Northern Brazil – excrete 1 mmol Na/d and have an average BP of 96/61 mm Hg Primitive people who are free of HTN adopt modern lifestyle, including increased intake of Na, their BP rises Rural Kenyan men move to Nairobi their Na excretion increases from 60 to 110 mmol/d BP rises over a few months DIET AND HYPERTENSION LARGE POPULATION STUDIES IN DEVELOPED COUNTRIES 1. Significant correlations between salt intake and hypertension has been found in most, but not all studies 2. The Intersalt Cooperative Research Group measured 24-h urine electrolytes and BP in > 10,000 individuals aged 20-59 y in 52 places around the world Showed a positive correlation between Na excretion and both SBP & DBP and the increase in BP with age Threshold: < 100 mmol per day Meta-analysis of randomized controlled trials A reduction of sodium intake lowers BP Urinary sodium excretion is associated with changes in BP DIET AND HYPERTENSION POTENTIAL FOR PRIMARY PREVENTION OF HTN A significant portion of CVD occurs in people whose BP is above the optimal level (120/80 mm Hg) but not so high as to be diagnosed or treated as HTN Active treatment of established HTN, as carefully as can be provided poses financial costs and potential adverse effects Most patients with established HTN do not make sufficient lifestyle changes, do not take medication, or do not take enough medication to achieve control Even if adequately treated according to current standards, patients with HTN may not lower their risk to that of persons with normal BP For every 3 mm Hg drop in SBP, 8 % decrease in mortality from stroke 5 % decrease in mortality from CHD DIET AND HYPERTENSION LIFESTYLE MODIFICATIONS Key point: Lifestyle modifications should be the cornerstone of the initial therapy for HTN Clinical studies show that the blood pressure-lowering effects of lifestyle modifications can be equivalent to drug monotherapy Lifestyle modifications is best initiated and sustained through an educational partnership between the patient and a multidisciplinary health care team - team members may vary by clinical setting - behavior change strategies include - Nutrition - Exercise - Smoking cessation services DIET AND HYPERTENSION LIFESTYLE MODIFICATION TO PREVENT AND MANAGE HYPERTENSION * Modification Recommendation Approx. SBP reduction Weight reduction Maintain normal body weight BMI = 18.5 – 24.9 Fruits, vegetables, low –fat dairy low saturated fat Reduce Na intake to no more than 100 mmol/d ( 2.4 g Na or 6 g natrium chloride) Engage in regular aerobic PA (brisk walking ,30-45 min per day, most days of the week) Limit consumption to 2 drinks/d for M, 1 for F 5-10 mm Hg/ 10 kg weight loss DASH* * eating plan Dietary Sodium restriction Increase physical activity Moderation of alcohol consumption *** 8-14 mm Hg 2-8 mm Hg 4-9 mm Hg 4-9 mm Hg 2-4 mm Hg Lifestyle modification* JNC7 recommendations For overall CVD risk reduction, stop DASH** indicates Dietary Approaches to Stop Hypertension smoking Alcohol consumption*** My point: Abstinence is better than moderation DIET AND HYPERTENSION DIETARY INTERVENTIONS DASH (Dietary Approaches to Stop Hypertension) eating plan in cohort studies - reduced incidence of congestive heart failure by 25% - reduced incidence of stroke by 17% in women Modest sodium restriction - reduces the amount of antihypertensive medications required Individuals vary in response to a reduced sodium intake Among hypertensives, African Americans, older patients, and patients with renal diseases seem to be more Natrium sensitive DIET AND HYPERTENSION DASH STUDIES (National Heart, Lung and Blood Institute) First study Tested nutrients as they occur together in the food (in the past, researchers tested various single nutrients, such as Mg and Ca; the studies – done mostly with dietary supplements and their findings were not conclusive) n = 459 adults, BP < 160/95 mm Hg 27% of the participants had hypertension 50% were women, 60% were African Americans Groups (3) with different eating plans (3): - similar to an American style - similar to an American style, but higher in fruit and vegetables - DASH diet All three plans used about 3,000 mg of sodium daily None of the plans were vegetarian or used specialty foods Results: Both the fruits and vegetables and DASH diet reduced BP DASH diet had the greatest effect, especially if patients had HTN The blood pressure reductions came fast – within 2 weeks of starting the plan DIET AND HYPERTENSION DASH STUDIES (National Heart, Lung and Blood Institute) Second study DASH-Sodium n = 412 participants, SBP 120-159 mm Hg, DBP 80–95 mm Hg 41% participants had HTN, 57% women, 57% African American Groups (2): control and DASH-Na diet with eating plans (2), followed for one month at each 3 Na levels: > 3,300 mg/d (high intake) 2,400 mg/d (intermediate intake) 1,500 mg/d ( lower intake) Results: Reducing dietary sodium lowered BP for both eating plans At each Na level, BP was lower on the DASH diet vs. other diet The biggest BP reduction was at DASH with 1,500 mg/d Na intake Those with HTN had the biggest reductions, but those without it also had large decrease With 1,500 mg/d Na – fewer headaches. DIET AND HYPERTENSION THE DASH DIET Food group Daily servings Grains & grain products 7-8 Vegetables 4-5 Fruits 4-5 Low-fat, or Fat-free Dairy 2-3 Serving sizes 1 slice bread 1 oz dry cereals ½ cup cooked rice pasta, cereals 1 cup raw leafy veg ½ cup cooked veg 6 oz veg juice 1 medium fruit ½ cup(90 g) fresh frozen, canned ¼ cup(45 g) dried 180 ml juice 240 ml milk 240 ml yogurt 45 g cheese Examples and notes whole wheat bread, English muffin, pita bread, bagel cereals, oatmeal, crackers Significance of each food group energy and fiber collards, kale, spinach, tomatoes squash, broccoli, artichokes, green beans, carrots, green peas apricots, banana, dates, grapes oranges, grapefruit, melons, plums raisins, strawberries, pineapples tangerines, mangos K, Mg, fiber fat-free(skim) or low-fat (1%) milk, fat-free or low-fat yogurt cheese Ca, protein K, Mg, fiber DIET AND HYPERTENSION THE DASH DIET Food group Daily servings Serving sizes Examples and notes Meats Poultry Fish 2 or less 85 g cooked select only lean, trim away visible fat meat, poultry, fish broil, roast, or boil instead of frying remove skin from poultry Significance of each food group protein, Mg Nuts, 4-5 per week 45 g nuts, Almonds, filberts, peanuts, walnuts Seeds nut butter, seeds sunflower seeds, sesame Dry beans ½ cup cooked beans Kidney beans, lentils, garbanzo energy, Mg, K, protein, fiber Fats Oils 2-3 1 tsp (5g) margarine Soft margarine 1 tsp vegetable oil Vegetable oil fat 27% en Sweets 5 per week 1 Tsp (15g) sugar jam, honey , syrup sweets should be low in fat jelly, sugar, jam, hard candy, fruit drinks, sorbet, ices The DASH eating plan is based on 2000 calories /day. The number of daily servings in a food group may vary from those listed depending on your caloric needs. DIET AND HYPERTENSION DIETARY FIBER - may reduce BP - results not consistent - most studies that show results used whole foods: - perhaps energy displaced and caused weight loss - other minerals in whole grains like Mg involved - role for fiber? - substituting whole grain for refined CHO in heart healthy diet reduces BP DIET AND HYPERTENSION When SFA is reduced to follow DASH diet it is either replaced with CHO or MUFA When SFA is replaced by CHO - increased SBP and DBP - especially when CHO is refined and has less dietary fiber - maybe Hyper insulinemia induced by high refined CHO leads to vascular resistance, Sodium retention and increased BP DIET AND HYPERTENSION When SFA is replaced by MUFA - BP especially diastolic is low - effect of MUFA disappears when total fat intake is high (> 37 %) - same effect in normo and hypertensive subjects - mechanism membrane fluidity Insulin sensitivity reduced structural alterations in arterial vascular smooth muscle cells improved vascular health DIET AND HYPERTENSION PUFA N-6 PUFA not much studied N-3 PUFA - either protective or no effect - dose needed for lowering BP is approx. 4 g/d - most effective in hypertensive than in normotensive individuals (useful for treatment and not for prevention) Mechanism increased endothelial derived relaxation factor works through NO, molecular aspect (+) Pg I3 and Tx A3 (vasodilation and anti-thrombosis) DIET AND HYPERTENSION LABEL LANGUAGE Food labels can help choose items lower in sodium and saturated fat & total fat. Look for the following: Phrase What it means SODIUM Sodium free or salt free Very low sodium Low sodium Low sodium meal Reduced or less sodium Light in sodium Unsalted or no salt added Less than 5 mg per serving 35 mg or less of sodium per serving 140 mg or less sodium per serving 140 mg or less sodium per 3 ½ oz (100 g) at least 25% less sodium than regular version 50% less sodium than the regular version No salt added to the product during processing FAT Fat free Low-saturated fat Low fat Reduced fat Light in fat Less than 0.5 g per serving 1 g or less per serving 3 g or less per serving At least 25% less fat than the regular version Half the fat than the regular version REFERENCES Rasmussen BM, et al. Effects of dietary saturated, monounsaturated, and n-3 FA on blood pressure in healthy subjects. AJCN, 2006, 83:221-226 th The 7 Report of the Joint Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure. The JNC 7 Report * JAMA 289: 2560-2572, 2003 Dietary Approaches to Stop Hypertension DASH Pubmed.org www.pcrm.org www.icsi.org QUESTIONS? QUESTIONS? QUESTIONS? QUESTIONS? QUESTIONS? QUESTIONS? QUESTIONS? QUESTIONS? QUESTIONS? QUESTIONS? QUESTIONS?