Dietetic Guidelines for Secondary Prevention of Cardiovascular Disease Alison Mead Chief Dietitian On behalf of UK Heart Health and Thoracic Dietitian’s Specialist Group of the BDA

UK HEART HEALTH GROUP UK HEART HEALTH GROUP UK Heart Health & Thoracic Specialist Group of British Dietetic Association –Approx 70 members Dietetic Guidelines: Diet in Secondary Prevention of CVD –Published August 2001 –1 st update August 2004 –2 nd update October 2006 In press

Previous Guideline recommendations 1. Increased omega 3 fat intake 2. Reduction in saturated fat with total or partial replacement by unsaturated fat 3. Mediterranean dietary advice for those that have suffered an MI

Literature Search Cochrane, DARE, MEDLINE, EMBASE to Jan 05 Identify all Systematic Reviews of Randomised Controlled Trials for diet and secondary prevention of CVD with the following outcomes: –Further CVD (MI, angina, stroke, PVD, CABG, PTCA) –Death –CV risk factors (lipids, weight, central obesity, BP, DM, raised homocysteine)

Inclusion Reviews were included if: –Outcome data from RCTs could be separated from other data –Intervention was some sort of dietary advice –At least one RCT was in people with CVD and no heterogeneity to those without –Outcomes Further CVD (MI, angina, stroke, PVD, CABG, PTCA) Death CV risk factors (lipids, weight, central obesity, BP, DM, raised homocysteine)

GRADING THE EVIDENCE: Evidence was graded on the quality of evidence –Excellent = 1, evidence from RCTs or SRs It was also graded on importance of outcomes –A= on morbidity or mortality –B= on a risk factor 1A

Quality Assessment

GUIDELINES: s ummary based on evidence 1A There are systematic reviews on the effects of the following dietary factors on cardiovascular disease or death: Omega 3 FatsMediterranean diet Low or modified fatAntioxidant vitamin supps Garlic supplementsGingko biloba Low GI dietsHomocysteine lowering therapies Multifactorial interventions

GUIDELINES: s ummary based on evidence 1B There are SR for dietary factors effect on cardiovascular risk factors: –Omega 3 Fats –Low fat/ 600kcal deficit –Fat replacement –Low GI diets –Garlic supplements –Homocysteine lowering therapies –Multifactor interventions

Omega-3 fat and mortality  Eating n-3 fatty acids or taking fish oil supplements (1g/d) both reduce mortality in patients that have had an MI (Bucher et al. 2002)  3 portions of oily fish/ week  or 1g/d from supplement (Docosahexanoate acid/ Eicosapentaenoic acid)  Not clear whether this is quantity of n-3 fatty acids are beneficial in CVD patients that have not suffered an MI. (Hooper et al 2004, Wang et al 2004)

Copyright ©2006 BMJ Publishing Group Ltd. Hooper, L. et al. BMJ 2006;332: Fig 3 Effect of omega 3 fatty acids on cardiovascular events.

Omega-3 fat and mortality In diabetics fish oil does not worsen glycaemic control or LDL levels. (Farmer 2002) Plant Based: Evidence for effectiveness of plant-based omega-3 fats (eg rapeseed oil/canola flax or linseed oil) is unclear. But, the effectiveness of the Mediterranean diet in the Lyon study, which gave out rapeseed margarine, means it is probably appropriate to suggest vegetarian sources of omega-3 fats for those who cannot take fish or fish oil.

Mediterranean diet: potentially protective post MI  More omega-3 fats, fruit & vegetables, less saturated fat & partial replacement by rapeseed or olive oil &  more emphasis on fresh (not ready prepared) foods ( Evidence presented in a SR, but based on only 1 RCT, so not strong) Years 5 Diet Control De Lorgeril et al Circulation 1999;99:779

Reduction in Saturated Fat A reduced or modified fat intake, followed for at least 2 years, results in a small reduction in risk of cardiovascular events –Up to 2 yrs - 96 events for every 100 people –> 2 yrs – 76 events for every 100 people

Antioxidants Epidemiological data was promising RCTs showed no benefit Vitamin E: –No effect on all cause mortality (RR 0.96, CI 0.84 to 1.1) or CVD risk (RR 0.97 CI 0.8 to 1.19) Skekelle 2004 –High doses (>400IU/d) increase risk of mortality (RR 1.04 CI 1.01 to 1.07) Miller 2005 Beta- carotene –Increase risk of death (OR 1.07 CI 1.02 to 1.11) and CVD death (OR 1.1 CI 1.03 to 1.17) Vivekananthan 2003

Ginko biloba, multi-factorial  Gingko biloba extract appears to increase pain-free walking distance modestly, in people with intermittent claudication (Pittler 2000)  Multifactorial interventions appear to be more effective than single dietary interventions at reducing mortality and morbidity in people with CVD (Ketola 2000)

Low GI, Homocysteine, Garlic No evidence as to whether low GI diets effect CHD mortality or events (Kelly 2004) No evidence as to whether plasma homocysteine lowering therapies (folate, Vit B12, B6) affect PAD progression (Hansrani 2002) –Two recent RCTs show no effect on events NORVIT Trial NEJM 2006, HOPE 2 NEJM 2006 No evidence of any beneficial effect of garlic supplements in people with peripheral arterial occlusive disease (Jepson, Kleijnen & Leng 1999)

Summary evidence level 1B Diet and Risk Factors  All dietary advice to reduce lipids etc is supplementary to cardioprotective diet.

Lipids Lipids  Lipid Reduction - Total Cholesterol 3-6% Statins more effective  Modified fat intake, including fish oils  Low GI diet (not conclusive)  Garlic (not conclusive)  Weight Loss  Stanol Esters & Plant Sterols (not yet published)

Mono (Olive, Rapeseed) or Poly (Sunflower, Walnut, Sesame)? Unclear Reduction in Total and LDL High doses of PUFA may reduce HDL Mediterranean theory Fish Oils – high doses reduces TG but increase total and LDL

Lipids Lipids  Lipid Reduction - Total Cholesterol 3-6% Statins more effective  Modified fat intake, including fish oils  Low GI diet (not conclusive)  Garlic (not conclusive)  Weight Loss (primary care)  Stanol Esters & Plant Sterols (not published)

Hypertension  Independent Risk Factor  Decrease 3- 5mmHg SBP reduces CHD risk by 10% and stroke by 15%  DASH Trial

Hypertension SRs Omega 3 fats –No effect on blood pressure (Hooper 2004, Morris, Sacks & Rosner 1993) –Small reduction in DBP in those with intermittent claudication (caution, small poor studies) All other SRs are from primary prevention so not included in guidelines (potassium, calcium, salt, weight)

Dietary Factors that affect Hypertension in primary prevention Salt Weight Reduction Alcohol Potassium Calcium Dairy Peptides (Isoleucine-Proline-Proline and Valine- Proline-Proline)

Homocysteine, Weight Loss Homocysteine, Weight Loss  Raised homocysteine levels can be reduced by supplementation with folic acid, alone or with vitamin B6 and B12  No SR to show whether this effect events  Weight Loss: Low fat & 600kcal deficit resulted in 4.2kg loss more than control

Blood Glucose, HbA1c, DM diagnosis No secondary prevention reviews

Limitations Lack of trials –Alcohol Only SRs of RCTs Patients that participate

Summary Main dietary recommendations that save lives are:  saturated fats & total/partially replace with unsaturated fats (rapeseed or olive oil)  omega-3 fat intake, the amount depends on diagnosis. Follow a Mediterranean diet (increase omega 3 fat, fruit and vegetables and fresh foods, reduction in saturated fat and processed foods ) Antioxidant supplements not effective