Breast Cancer and the Mediterranean Diet

Breast cancer is the most common type of cancer among women. Factors that predispose people to breast cancer include older age, hereditary transmission, late menopause (menopause after age 55), sex, a sedentary lifestyle and an unhealthy diet. Positive lifestyle changes, weight loss, and not smoking or drinking alcohol can prevent 30% of all breast cancers. The easiest and most effective way to eat healthily is undoubtedly the Mediterranean diet. 

Being overweight or obese is among the most important factors that increase breast cancer risk. But how does this mechanism work?

Having more fatty tissue raises estrogen levels in the body, increasing the risk of developing breast cancer. Fatty tissue is also known to retain certain toxins in the body (for example, dioxins). In particular, to reduce fatty tissue in estrogen-dependent breast cancer, overweight or obese people diagnosed with breast cancer should be helped to reach their normal weight, unlike in other types of cancer.

Overweight women also have high levels of another hormone, insulin. Higher insulin levels have been linked to certain cancers, including breast cancer.

Although gaining weight can increase your cancer risk, remember that it is a manageable condition

One study found that individuals following the Mediterranean diet lost a significant amount of body weight and also experienced a significant reduction in fasting glucose and insulin levels.

In people diagnosed with cancer, if inadequate nutrient intake generally results from chemotherapy side effects (loss of appetite, nausea, vomiting, etc.) or catabolism (metabolic breakdown) in the body, action should be taken accordingly. Support from a nutrition professional will be beneficial, regardless of their weight at diagnosis.

Whether or not you are overweight, we know that avoiding weight gain is beneficial

The goal for everyone should be to reach their ideal weight and maintain fitness. The Mediterranean diet, with its countless benefits, may be a good starting point.

Mediterranean-style eating emphasizes fresh vegetables and fruit, grains, legumes, nuts, fish and olive oil, and favors whole-grain bread. In contrast, consumption of trans fats, animal fats, red meat, poultry, milk and dairy products is kept low.

Many foods in the Mediterranean diet contain beneficial chemical compounds. These include lycopene (tomatoes); capsaicin (hot peppers); organosulfur compounds (onions, garlic); isothiocyanates, indole-3-carbinol and sulforoptan (cruciferous vegetables); polyacetylenes (squash, carrots); monoterpenes (oranges, lemons); ginkgetin (capers); and ferulic acid and spermidine (whole grains).

Foods that affect breast cancer risk

Milk

One of the most controversial issues concerning milk is the idea that it may pose a breast cancer risk because milk consumption raises the estrogen hormone levels taken into our bodies. According to the results of one study on this subject, a significant conclusion could not be drawn between the two. Another issue concerning milk is the link between cancer and its lactose content. As lactose is digested, it increases calcium absorption from the intestines. Its slow effect on raising blood sugar is also an advantage. One study presented findings suggesting that consumption of low-fat milk and dairy products protects against cancer.

The American Cancer Society makes no specific recommendation on milk consumption for cancer prevention. A study published in the British Medical Journal recommended consuming 0-2 servings of milk and dairy products daily.

- Related topic: MILK and HEALTH – A Topic of Interest and Surprising Findings!

Phytoestrogens

Plant estrogen is another name for phytoestrogens, which occur in higher concentrations in soy and similar foods. Although they also occur in legumes, they are most abundant in soy products. When certain types enter the body, they interact with estrogen hormone receptors and produce one-third of estrogen's effect. Some studies have reported protection against breast cancer because they prevent vascularization (blood vessel formation) in breast tissue. However, particularly women with hormone-positive breast cancer should avoid consuming large amounts of soy for a "cure"; no warning has been reported about consuming normal amounts.

Flaxseed has a phytoestrogenic effect because of the lignans it contains. Studies have suggested that consuming high amounts increases estrogen levels and raises cancer risk (see flaxseed and breast cancer).

Dietary fiber / high-fiber foods

Unprocessed whole grains such as oats, barley, wheat, corn and rice contain complex carbohydrates, vitamins, minerals and healthy fiber. Regular consumption of appropriate amounts of dietary fiber (25-30 gr daily) lowers estrogen levels and also eliminates estrogen reabsorption from the small intestine, and thus can reduce breast cancer risk.

We can meet our daily fiber needs by eating 1 plate of legumes + salads + 1-2 servings of fruit.

The high fiber content of the traditional Mediterranean diet has also been shown to increase stool bulk and estrogen excretion, potentially reducing plasma estrone and estradiol concentrations.

Alcohol

It is well known that alcohol causes liver cancer; alcohol consumption is an established cause of at least 7 types of cancer. It has classified alcoholic beverage consumption as a group 1 carcinogen. It also found that it can cause colorectal and breast cancers. We now recommend not consuming alcohol in terms of cancer risk. For people who choose to drink, it recommends limiting consumption to 1 drink daily for women and 2 for men.

Carbohydrate and sugar consumption

Some studies suggest that excessive carbohydrate intake (for example, obtaining more than half of daily energy from carbohydrates) may increase breast cancer risk because it raises the amount of insulin secreted in the body. Increased insulin in the body is thought to be related to cancer because it raises blood levels of insulin-like growth factor (IGF) and sex hormones such as estrogen and androgen. Although this has been demonstrated in many studies, prospective studies are needed.

The carbohydrates we consume should be complex and have a low glycemic index, without causing excessive insulin release (see which are the best low-glycemic-index foods?). Simple / refined carbohydrates (biscuits, cakes, white bread, sugar, white flour products, sweets and processed foods) are also digested quickly, can cause hunger pangs and may lead to greater carbohydrate intake.

There is no need to count calories in the Mediterranean diet. Remember that losing weight is possible by removing refined and processed foods from your diet.

To consume complex carbohydrates, choose bread made with wholemeal flour, make sure to include legumes in your eating plan, and choose fruit for snacks instead of processed foods containing corn syrup. The important point here is not to fall for the misconception that “sugar consumption causes cancer". Excessive sugar consumption increases cancer risk by causing excess weight and obesity, along with the metabolic-genomic changes associated with these conditions.

- Related topic: What Is Starch, What Is Fructose, and How Does Excess Sugar Turn into Fat?

Red meat

The American Cancer Society's 2020 Diet and Physical Activity Guideline increased its emphasis on consuming less processed and red meat. Recent studies suggest that red / processed meats may also play a role in increasing breast cancer risk.

Fruit and vegetables

Fruit and vegetables are among the most important elements of a healthy diet thanks to their many nutrients, balanced food composition (the balance of carbohydrates, fats and proteins) and high dietary fiber content. A study among 3000 menopausal women found 37% less breast cancer in the group consuming more vegetables. The World Health Organization recommends around 5 servings of vegetables and fruit daily.

Conclusion

We see that many foods making up the Mediterranean diet are effective both in weight management and in reducing breast cancer risk.

The fiber, antioxidants, flavonoids, vitamins and carotenoids regularly consumed in the Mediterranean diet can naturally reduce excess estrogen and neutralize free radicals. In this way, the Mediterranean diet may protect against breast cancer risk.