This trial studies the effects of a dietary intervention based on the Alternative Healthy Eating Index (AHEI) on inflammatory markers and breast density in healthy participants. The AHEI is a quantifiable measure of diet quality designed to target food and macronutrient sources that are associated with chronic disease risk. Adherence to the AHEI may be associated with a reduction in inflammatory biomarkers and sex steroid hormone levels compared to other dietary patterns/scores.

OUTLINE:

DIETARY INTERVENTION: Participants receive dietary counseling with a dietitian in person or via telephone to support adherence to a diet based on the AHEI guidelines once weekly for up to 12 weeks.

DUAL X-RAY ABSORPTIOMETRY (DXA) ONLY STUDY: Participants undergo DXA scan for breast density measurement at baseline and at 12 weeks.

Inclusion Criteria:

• Women will be eligible if they are nulliparous, aged 18-30, and score below 75 on the AHEI. Study eligibility will be assessed via online screening questionnaire and online Food Frequency Questionnaire (FFQ). These criteria were chosen because of our focus on the years before first birth as a critical period for establishing breast cancer risk
• Participants must be able to come to two clinic visits, complete questionnaires in English, and will be required to discontinue all vitamins and nutritional supplements during the study period
• DXA ONLY PILOT STUDY: Participants must be able to come to one visit in the Prevention Center where they will receive the consent form and undergo the DXA scan. No intervention will occur and there will be no follow-up assessments or measurements beyond the DXA scan

Exclusion Criteria:

• Women will be ineligible if they are postmenopausal, pregnant, taking hormone therapy (e.g., oral contraceptives), or have chronic illnesses that are known to affect gastrointestinal absorption of nutrients
• Women who obtain a score of >= 75 on the AHEI are also ineligible
• DXA ONLY PILOT STUDY: Women who are pregnant