Serum Levels of Advanced Glycation End-products After Dietary Intervention in Hypertensive Patients

Cardiovascular disease (CVD) is considered the main cause of mortality in the western world. There are many factors that contribute to the onset and progression of cardiovascular disease, including hypertension. Hypertension is a multi-factorial condition that includes nutritional disorders in its causality line. It is believed that advanced glycation end-products (AGEs) is one of the pathophysiological causes that explain the occurrence of high blood pressure in diabetic patients. This study has the role of describing the protocol of a randomized clinical trial aiming to evaluate changes in serum levels of end products of advanced glycation after an intervention for eating habit changes in hypertensive individuals.

The investigators designed a randomized clinical trial, with non-blinded assessment of outcomes. Participants will be recruited from the outpatient clinic for hypertension of a public hospital in Porto Alegre, aged from 40 to 80 years old and without diabetes. Hypertension is defined as systolic blood pressure ≥ 140 mmHg, diastolic blood pressure ≥ 90 mmHg, or antihypertensive medication use. Participants will be assigned to one of two groups. The intervention group will receive monthly educational intervention sessions for low salt diet, high in fruits and vegetables, and low in processed foods for a period of 6 months. Besides these, the intervention group will receive a standard telephone interview every two weeks to motivate them to follow the diet. The control group will receive the usual counseling for low sodium diet in monthly appointment with a dietitian, following the hypertension care clinic protocol.

This study aims to investigate if there are significant changes in serum levels of advanced glycation end products, after the nutritional intervention with diet guidance in fruits, vegetables, low in sodium and processed foods in hypertensive patients because several studies have shown that less processed food rich in antioxidants with low sodium content, play an important role in reducing levels of AGEs which are precursors of vascular inflammation and progression of cardiovascular diseases.

There will be a randomized, non-blinded, parallel-group clinical trial comparing serum AGESs level in patients randomized to receive an educational program of diet counseling or the usual care.

Study population: Hypertensive patients attending the outpatient clinic for hypertension treatment at a university-affiliated hospital in southern Brazil.

Intervention group - Nutritional counseling implemented by a dietitian for a low sodium diet rich in fruits, vegetables, low fat dairy foods, and low in processed foods. Patients will be evaluated every month.

Control group - usual care of hypertensive patients. Patients will be evaluated after 6 months.

Eligibility Criteria:
Inclusion Criteria:

* It will be included patients aged between 40 and 80 years old,
* diagnosed with hypertension defined by systolic blood pressure ≥ 140 mmHg, diastolic blood pressure ≥ 90 mmHg,
* or the use of drugs for hypertension; patients not following nutritional counseling in the last 6 months.

Exclusion Criteria:

* will be patients with inflammatory diseases, receiving chemotherapy treatment,
* diagnosed with diabetes mellitus,
* referred for nutritional counseling or unable to conduct the interview and to participate in the intervention program,
* pregnant women and nursing mothers.