Researchers in Iran studied 213 women to understand how different eating patterns might affect breast cancer risk. They found that women who ate a “Western” diet—high in processed foods, red meat, and unhealthy fats—had a higher chance of developing breast cancer before menopause. Interestingly, eating a healthy diet with lots of vegetables and whole grains, or a traditional diet, didn’t show the same increased risk. This study suggests that the types of foods we choose to eat may play a role in breast cancer development, especially for younger women.

The Quick Take

  • What they studied: Whether the types of foods women eat regularly are connected to their risk of getting breast cancer
  • Who participated: 106 women with breast cancer and 107 women without breast cancer, all living in Ahvaz, Iran. The study focused on women before menopause (younger women).
  • Key finding: Women who regularly ate a Western-style diet (processed foods, red meat, unhealthy fats) were about 4 times more likely to have breast cancer compared to those who didn’t eat this way
  • What it means for you: If you’re a younger woman, choosing healthier foods and limiting processed foods may help reduce your breast cancer risk. However, this is one study in one location, so talk with your doctor about your personal risk factors and diet choices.

The Research Details

This was a case-control study, which means researchers compared two groups of women: those who had been diagnosed with breast cancer and those who hadn’t. They asked both groups detailed questions about what they ate using a food questionnaire with 147 different foods. The researchers then grouped these 147 foods into 20 categories (like grains, vegetables, meats, etc.) to identify eating patterns. Using statistical analysis, they found three main dietary patterns: a healthy pattern, a Western pattern, and a traditional pattern. They then looked at whether each pattern was connected to breast cancer risk, while accounting for other factors that might affect cancer risk like age and family history.

Looking at overall eating patterns is more realistic than studying single foods, because people don’t eat foods in isolation—they eat combinations of foods. This approach helps researchers understand how the whole diet affects health. The case-control design is efficient for studying diseases like cancer that take time to develop.

This study had a reasonable number of participants (213 total) and used a detailed food questionnaire. However, the study was conducted in one city in Iran, so results may not apply to all women everywhere. The researchers adjusted their analysis for other factors that could affect cancer risk, which strengthens the findings. The Western diet finding was statistically significant, meaning it’s unlikely to be due to chance, though the confidence interval is fairly wide, suggesting some uncertainty in the exact risk level.

What the Results Show

The study identified three distinct eating patterns among the women studied. The Western dietary pattern—characterized by processed foods, red meat, refined grains, and unhealthy fats—showed a strong connection to breast cancer risk in premenopausal women (younger women before menopause). Women following this pattern were about 4.2 times more likely to have breast cancer. This association remained strong even after researchers accounted for other factors like age and family history. The healthy dietary pattern, which included vegetables, fruits, whole grains, and lean proteins, showed no increased risk. Similarly, the traditional dietary pattern showed no connection to breast cancer risk.

The study found that dietary patterns matter more than individual foods when looking at cancer risk. The fact that only the Western pattern showed increased risk suggests that it’s the combination of processed foods and unhealthy fats that may be problematic, rather than any single food. The lack of association with healthy and traditional patterns is encouraging, suggesting that eating well may be protective.

Previous research has linked individual foods and nutrients to breast cancer risk, but this study adds to growing evidence that overall eating patterns are important. Many studies worldwide have found connections between Western-style diets and various cancers. This Iranian study supports those findings specifically for breast cancer in younger women, though most previous research has focused on older, postmenopausal women.

This study was conducted in one city in Iran, so results may not apply to women in other countries or regions with different food availability and eating habits. The study is relatively small (213 women), which means the results need confirmation in larger studies. Because this is a case-control study, researchers asked women to remember what they ate in the past, which can be inaccurate. The study focused on premenopausal women, so we don’t know if the same pattern applies to older women. Finally, this study shows association (connection), not causation (proof that the diet causes cancer).

The Bottom Line

If you’re a younger woman, consider reducing processed foods, red meat, and unhealthy fats in your diet. Instead, focus on eating more vegetables, fruits, whole grains, and lean proteins. This recommendation has moderate confidence based on this study, but is supported by broader nutrition science. Discuss your personal breast cancer risk factors with your doctor, as diet is just one piece of the puzzle.

Younger women (premenopausal) should pay particular attention to these findings. Women with a family history of breast cancer may find this especially relevant. However, these findings don’t mean older women should ignore diet—healthy eating benefits everyone. Men should also eat well, though this study focused on women.

Dietary changes don’t produce immediate results. Cancer develops over many years, so eating well now may help reduce risk over time. You might notice other health benefits from dietary improvements (better energy, weight management) within weeks to months, but cancer risk reduction takes years.

Want to Apply This Research?

  • Track your daily intake of processed foods, red meat, and unhealthy fats (aim to reduce these), while monitoring servings of vegetables, fruits, and whole grains (aim to increase these). Use the app to log meals and get weekly summaries of your dietary pattern.
  • Set a specific goal like “Replace one processed food with a whole food each day” or “Add one extra vegetable serving to dinner.” Use the app to log this change and track your progress over 4 weeks.
  • Use the app to categorize your meals into dietary patterns (Western, healthy, traditional) monthly. Track trends over 3-6 months to see if you’re shifting away from Western-pattern eating toward healthier patterns. Share results with your healthcare provider.

This research suggests an association between Western dietary patterns and breast cancer risk in younger Iranian women, but does not prove that diet causes breast cancer. Individual cancer risk depends on many factors including genetics, family history, hormones, and lifestyle. This study should not replace medical advice from your healthcare provider. If you have concerns about breast cancer risk, consult with your doctor about screening, prevention strategies, and your personal risk factors. Always discuss major dietary changes with your healthcare team, especially if you have existing health conditions or take medications.