Mediterranean diet helps breast cancer survivors with weight goals

Relation

Braakhuis A, Campion P, Bishop K. The effects of nutrition education on weight and health biomarkers in breast cancer survivors.Med Sci (Basel). 2017;5(2):12.

Objective

To determine the effects of dietary changes on weight, waist circumference, BMI, blood lipid profiles, and glucose profiles in breast cancer survivors

Draft

Six-month, 3-arm, parallel randomized control trial with baseline testing and post-intervention testing

Participant

Fifty postmenopausal women aged ≥50 years from Auckland, New Zealand, previously diagnosed and treated for stage 1, 2, or 3 breast cancer; all women included in the study had a BMI >25 and had completed treatment (chemotherapy and surgery) at least 3 months and less than 3 years (including hormone therapy) before study entry. Participants were excluded if they were taking anti-inflammatory medications, drinking more than 2 alcoholic beverages per day, smoking tobacco, or having poorly controlled diabetes mellitus. Women of any ethnicity were eligible to participate.

intervention

Participants were randomly assigned to 1 of 3 arms:

Arm 1: Mediterranean diet

Arm 2: Healthy, low-fat diet

Arm 3: No treatment (control)

Arms 1 and 2 received 6 group nutrition and lifestyle training sessions with 6 summary newsletters once a month.

Study parameters assessed

Body weight, BMI, waist circumference, complete lipid profile, hemoglobin A_1c(HbA_1c), adherence to Mediterranean eating habits (using the PREDIMED questionnaire), quality of life score (Functional Assessment of Cancer Therapy - Breast [FACT-B] questionnaire), participation in group training, and 3-day food diary (completed once during the intervention period).

Primary outcome measures

Change in body weight, BMI and waist circumference

Key insights

Participants who followed the Mediterranean diet had significantly greater weight loss (-1.61 kg), lower BMI (-1.02), and reduced waist circumference (-1.40 cm). These parameters also improved in the low-fat diet group, but to a lesser extent (-1.35 kg weight loss, -0.56 BMI, -1.31 cm waist circumference). The control arm gained weight (+1.10 kg) and had an increase in BMI (+0.58) and waist circumference (+1.94).

Practice implications

Obesity and overweight are associated with an increased risk of breast cancer¹and worse prognosis for breast cancer survivors.²Mechanisms related to obesity that are thought to influence breast cancer progression include increased levels of circulating insulin and insulin-like growth factors, sex hormones, and cytokines released from adipose tissue.³In this study and in others⁴Breast cancer survivors tend to gain weight during and after cancer treatment. Targeted treatment strategies such as improved diet and exercise benefit our patients directly by improving markers of cancer progression and indirectly by reducing weight.

This study compared 2 nutritional interventions with a no-treatment control arm and found significant improvement in weight, BMI, and waist circumference in the Mediterranean diet arm and some improvement in the healthy low-fat diet arm. Other studies have observed a similar trend of improving weight loss and waist circumference on the Mediterranean diet compared to a low-fat diet.^5.6But the Mediterranean diet is more than just an effective weight loss diet in this population.

The Mediterranean diet is a great option for breast cancer survivors. It focuses on vegetables, fruits, legumes, whole grains, fish and extra virgin olive oil (EVOO), ingredients that we know are important for your health. Additionally, it is a colorful diet rich in phytochemicals including antioxidants, anti-inflammatories and polyphenols. The Mediterranean diet has been shown to reduce markers associated with metabolic syndrome (high-sensitivity C-reactive protein [hs-CRP], interleukin [IL]-7, IL-18 and insulin resistance),⁷which is associated with increased cancer incidence and cancer-related mortality, and markers related to inflammation⁸and lipid oxidation.⁹It has also been shown to reduce the incidence of breast cancer¹⁰and reduce breast cancer recurrence.¹¹

What is the take-home message? Breast cancer survivors need your help maintaining or losing weight after cancer treatment. Without any intervention, a trend toward weight gain was observed, worsening her prognosis. Choosing a diet rich in phytochemicals provides them with additional benefits through various mechanisms, and the Mediterranean diet is a well-documented good option. Nutritional counseling was found to be effective in this study; However, other studies have found improved compliance when patients have hands-on experiences such as cooking classes.¹²Regardless of this study, let's not forget the added importance of exercise for weight loss and breast cancer survival!