Effectiveness of Mediterranean Diet vs. DASH Diet in Reducing

Cardiovascular Risk Factors

Hannah LapkinGNUR 450

Background• More than 2, 200 Americans die daily from

CVD– One death every 39 seconds– Cause of 1/6 deaths in U.S. in 2007

• Major risk factors:– Hypertension (>120/80 mmHg): 33.5%– High Cholesterol (>240 mg/dl): 15%– Obesity (BMI > 30 kg/m2): 33.7%

• Financial Implications– Estimated cost of CVD: $268 billion – Cardiovascular operations/procedures

increased 27% from 1997

PICOT Question• In patients with the cardiovascular disease risk

factors of hypertension and elevated cholesterol, how does the Mediterranean diet compare with the DASH diet in effectively reducing blood pressure and serum cholesterol levels over six months with bi-monthly counseling with an RD?– P: High-risk CVD patients– I: Mediterranean diet– C: DASH diet– O: Reduced blood pressure and cholesterol– T: 6 months

• Significance

Literature Review• DASH Diet

– High consumption of fruits, vegetables, whole grains, nuts/legumes, low-fat dairy products

– Low consumption of sodium, red/processed meats, saturated/total fat

– Used in U.S. for prehypertensive/hypertensive individuals • Studies show significant reductions in total/LDL cholesterol and

estimated CHD risk

• Mediterranean Diet– Composed of:

• Abundance of plant foods• Minimal red and processed foods• Moderate amount of dairy products• Olive oil as main lipid source• Low-moderate consumption of wine with meals

– Evidence demonstrates:• Lower serum triglycerides, cholesterol, and systolic/diastolic blood

pressure

Table of Relevant StudiesStudy Results Gaps

Kastroini, Milionis, Esposito, Guigliano, Goudevenos, & Panagiotakos. 2011

-Adherence to Med. Diet reduced waist circumference, triglycerides, hypertension, glucose, and increased HDL

-No specified details of Med. Diet-Inability to control for confounders

Levitan, Wolk, & Mittleman. 2009.

-Greater consistency with DASH associated with lower heart failure events and reduced blood pressure and LDL/HDL cholesterol

-Only looked at men ages 45-79-DASH diet component score was not validated

Serra-Majem, Roman, & Estruch. 2006

-Med. Diet associated with improved lipoprotein levels, metabolic syndrome, and myocardial and CVD mortality in obese patients with previous MI

-Identified that no previous RCT had determined the extent to which the Med. diet is more effective than typically low-fat CVD diet (DASH)

Sofi, Abbate, Gensini, & Casini. 2010

-Adherence to Med. diet has significant protective factors on overall mortality and cardiovascular incidence and mortality

-Studies of short duration-Limited ability to transfer adherence score to the general population

Swain, McCarron, Hamilton, Sacks, & Appel. 2008.

-All diets improved cardiovascular risk factors but the blood pressure, cholesterol, and overall risk was lowered the most in higher protein diets.

-Only a 19-week study-Didn’t investigate adherence of each diet in free-living individuals

Tyrovolas & Panagiotakos. 2010

-Fish consumption lowers CVD risk with decreased HTN, high cholesterol, and all-cause mortality. -Daily fruit/vegetable consumption reduces risk of MI

-Identified that studies need to determine the feasibility of the integration of the Mediterranean diet into other countries and cultures.

Search Strategy

• Databases– EbscoHost– Ovid– Pub Med

• Search Terms – Cardiovascular

disease– Heart disease– DASH diet– Mediterranean– Cholesterol– Hypertension

• Study inclusion Criteria– English-language– Years 2007-2012

Design

• Pretest-Posttest experimental design

• Randomized into two diet arms – Each of 50 individuals – Stratified equally into

men and women

• 6 months• Bi-monthly counseling

with a trained RD• Evaluation

– BP readings at baseline, monthly, and at end

– Serum cholesterol values assessed at baseline, 3-month mark, and end

– Food frequency questionnaires bi-monthly

• Adherence test

DASH Diet Mediterranean Diet

Energy Level 2100 kcal 2100 kcal

Total Fat 27% 37%

Saturated Fat 6% 6%

Carbohydrates 55% 45%

Protein 18% 18%

Cholesterol 150 mg 150 mg

Fiber 30 g 30 g

Recommendations

6-8x whole grains, 4-5x fruit, 4-5x vegetables, 2-3x low-

fat/fat-free dairy, 2-3x fats/oils, sweets/added sugar

(5x weekly), nuts/seeds/legumes 4-5x

weekly)

1-2x fruit, 2+ vegetables, 1-2x olive oil, bread, pasta, rice, couscous (preferably

whole grain) at every meal; 2x low-fat dairy with herbs and spices (instead of salt) daily; 2x white meat, 2+ seafood, 2-4x eggs, 2+

legumes, 3+ potatoes, less than 2x red/processed meats, less than 2x sweets weekly,

wine in moderation

Sample• Method

– Research nurses will recommend study to patients at a cardiac unit that meet inclusion/exclusion criteria

– Stratified random sampling by gender

• Size– 50 men/50 women– 50/each diet arm

• Inclusion/Exclusion

Inclusion Criteria

Exclusion Criteria

Blood pressure

>120/80 mmHg >160/100 mmHg

Cholesterol >220 mg/dL >280mmHg

Diet Must accept and enjoy diet plans from BOTH arms

Food allergies

Age > 35 years < 35 years

Medication NOT on blood pressure or cholesterol medication

ON blood pressure or cholesterol medications

Methods for Data Collection• Blood pressure readings

– Baseline– Monthly

• Serum cholesterol blood draws– Baseline– Month 3– End of Month 6

• 2008 NHANES Food Frequency Questionnaires– 110-food item list – Bi-monthly with counseling sessions – Ensure adherence

• Food Diaries– To review with RD and ensure accurate FFQ responses

Intervention Protocol

• Two RDs working in a cardiology unit will deliver intervention through bi-monthly counseling– Assigned to either DASH/Mediterranean Diet arm– Must be similar in personality

• Will take personality test to ensure similarity • Training program to ensure fidelity

– Trained on specifics of each diet, nutrient composition and energy requirements, optimal methods to implement the goals

– Ensure RDs are equally knowledgeable on their assigned

diet arm and can adequately counsel participants.

Procedures for Data Collection

• Bi-monthly counseling sessions– Review and analyze food diaries– Offer suggestions on improving adherence to assigned diet– Provide assistance on following assigned diet– RD will chart on each counseling session using de-identified data

(identification numbers for participants)

• Food Frequency Questionnaires completed by participants at time of counseling session

• Trained laboratory technician will:– Take blood pressure readings monthly– Do blood draws at baseline, 3-month mark, end to assess cholesterol

values

• Research analysts will assess– RD chart notes– Food Frequency Questionnaires– Blood pressure readings– Serum cholesterol values

Measures for Data Collection• Blood pressure readings and blood tests

– Reliability: extremely reliable• Laboratory technicians will also be highly-trained to enhance

reliability

– Validity: extremely valid• Highly-trained lab technicians also enhances validity

• Food Frequency Questionnaires– Reliability: Moderately reliable

• Hindered due to self-reporting; may report what they think researchers want to see

– Validity: Deemed valid sources of adherence in a number of nutritional experiments

Proposed Data Analysis Plan

• Independent t-test– Comparing different diet

arms in two groups

• Repeated measures analysis of variance (ANOVA)– Study participants will be

assessed at 3 different points of time

Human Subjects Issues

• Approved by Loyola IRB• Informed of study through research nurse• De-identified data to minimize potential biases

– Identification numbers received at time of consent• Participants will consent to participation through signed waiver

– Informed consent waiver• Statement of participant status• Study goals• Type of data collected and procedures used• Nature of commitment• Sponsorship of study• Method of participant selection• Potential risks and benefits• Alternative treatments

• No diet therapy was unethical

Study Challenges• Financially difficult

– Bi-monthly counseling for 100 participants

• Time commitments– Bi-monthly counseling appointments– Food logging

• Small sample size– Maybe too small for statistical power

• Potential limited diversity– Consequently limiting generalizability

• Selection bias due to convenience sampling– Threat to validity

• Self-reporting inaccuracies of food frequency questionnaires– Only provide broad, general view of adherence

ReferencesFundacion Dieta Mediterranea. (2011). The FDM presents the new Mediterranean diet pyramid. Retrieved from

http://fdmed.org/en/the-fdm-presents-the-new-mediterranean-diet-pyramid/

Kastroini, C., Milionis, H., Esposito, K., Guigliano, D., Goudevenos, J., & Panagiotakos, D. (2011). The effect of Mediterranean diet on metabolic syndrome and its components: A meta-analysis of 50 studies and 534,906 individuals. Journal of the American College of Cardiology, 57(11), 1299-1313.

Levitan, E., Wolk, A., & Mittleman, M. (2009). Relation of consistency with the dietary approaches to stop hypertension diet and incidence of heart failure in men aged 45 to 79 years. American Journal of Cardiology, 104, pp. 1416-1420.

Roger, V., Go, A., Lloyd-Jones, D., Adams, R., Berry, J., Brown, T., Carnethon, M., Dai, S., de Simone, G., Ford, E., Fox, C., Fullerton, H., Gillespie, C., Greenlund, K., Hailpern, S., Heit, J., Ho, P., Howard, V., Kissela, B., Kittner, S., Lacklund, D., Lichtman, J., Lisabeth, L., Makuc, D., Marcus, G., Marelli, A., Matchar, D., McDermott, M., Meigs, J., Moy, C., Mozaffarian, D., Mussolino, M., Nichol, G., Paynter, N., Rosamond, W., Sorlie, P., Stafford, R., Turan, T., Turner, M., Wong, N., & Wylie-Rosett, J. (2010). Heart disease and stroke statistics—2011 update: A report from the american heart association. Circulation, 123, pp. e18-e209.

San Vincente, R., Perez, I., Ibarra, J., Berranondo, I., Uribe, F., Urraca, J., Samper, R., Aizpurua, I., Almagro, F., Andres, J., & Ugarte, R. (2008). Clinical practice guideline on the management of lipids as a cardiovascular risk factor. Retrieved from http://www.guideline.gov/content.aspx?id=15711&search=basque+mediterranean+diet

Serra-Majem, L., Roman, B., Estruch, R. (2006). Scientific evidence of interventions using the Mediterranean diet: A systematic review. Nutrition Reviews, 64 (2), p. S27-S47.

Sofi, F., Abbate, R., Gensini, G., & Casini, A. (2010). Accruing evidence on benefits of adherence to the Mediterranean diet on health: An updated systematic review and meta-analysis. American Journal of Clinical Nutrition, 92, pp. 1189-1196.

Swain, J., McCarron, P., Hamilton, E., Sacks, F., Appel, L. (2008). Characteristics of the diet patterns tested in the optimal macronutrient intake trial to prevent heart disease (omniheart): Options for a heart-health diet. Journal of the American Dietetic Association, 108, pp. 257-265.

Tyrovolas, S. & Panagiotakos, D. (2010). The role of Mediterranean type of diet on the development of cancer and cardiovascular disease in the elderly: A systematic review. Maturitas, 65, pp. 122-130.

U.S. Department of Health and Human Services (2006). Your guide to lowering your blood pressure with DASH: Dash eating plan. NIH Publication No. 06-4082.