Introduction
Do you think dairy is scary? One of the top questions I get asked as a cancer dietitian is if dairy is safe. I am here to set your mind at ease – YES. Not only is dairy safe, some forms of dairy are packed with nutrients that have numerous health benefits and may even play a role in preventing some forms of cancer!
Why are people concerned about dairy?
A common concern with dairy is related to the hormone IGF-1 (insulin-like growth factor) found in milk. IGF-1 is a hormone similar in structure to insulin, hence its name. It’s a protein that helps our bodies grow and develop. Too much IGF-1 in one’s body has been associated with an increased risk of several cancers, including breast, prostate, and colorectal cancer. Milk, particularly cow’s milk, naturally contains IGF-1. The concentration of IGF-1 in milk can vary based on factors like the cow’s breed, age, and diet.
IGF-1 in Dairy – Should I be Concerned?
Before you pour all the milk down the drain, know that the relationship is more complex. Scientists have been studying this idea for a long time. And from what they’ve found, the story is not so simple.
Small Amounts
Even though milk contains IGF-1, the amount is not huge compared to what our bodies already make. Our bodies naturally produce IGF-1 to help us grow, and the amount we get from milk is small in comparison.
Digestion Matters
When we drink milk, our stomachs and intestines break down the proteins, including IGF-1. This means our bodies might not absorb all of it, and what we do absorb might not affect us the same way as IGF-1 that our bodies make themselves.
Mixed Evidence
Scientists have studied whether drinking milk with IGF-1 leads to more cancer. Some studies say yes, but others say no. It’s not clear-cut. Other factors like genes, exercise, and overall diet also play a big role in cancer risk.
Nutrients in Dairy
Dairy is not just about IGF-1. These foods are nutrient powerhouses packed with so many different vitamins and minerals that support overall health.
Calcium
Calcium is not just important for strong bones and teeth. Having enough calcium in one’s diet may also reduce the risk of colorectal cancer. Calcium helps to regulate cell growth and differentiation, potentially decreasing the likelihood of cancerous changes in cells. Calcium is considered a nutrient of concern in the USA – meaning most people are not getting enough. One cup serving of milk provides roughly 25% of your Daily Value or a quarter of your calcium needs for the whole day – that’s alot!
Vitamin D
Many dairy products are fortified with vitamin D, which is ALSO a nutrient of public health concern. Vitamin D is required for calcium absorption and bone health. It also plays a role in immune function and may help reduce the risk of cancers such as colorectal, breast, and prostate cancers.
Probiotics
Some dairy products, such as yogurt and kefir, contain probiotics—beneficial bacteria that support gut health. A healthy gut microbiome is associated with a reduced risk of colorectal cancer.
Sphingolipids
Sphingolipids are a part of the milk fat globule membrane (MFGM) that encloses fat droplets in milk. Cell studies suggest that sphingolipids, particularly sphingomyelin, may have anti-cancer properties. Sphingomyelin’s metabolites, ceramide and sphingosine, may inhibit cell growth and trigger cell death, which can influence cancer growth.
Closing
So, what does this mean for you? It means that enjoying milk in moderation can be part of a balanced diet. Low-fat or reduced-fat dairy is recommended for the general public to prevent weight gain and reduce excess intake of saturated fats. For those who are going through treatment, however, whole milk and high fat dairy products may help reduce weight loss and encourage weight gain from cancer induced malnutrition. Rather than fear a food, focus on what role it has, and what nutrients it provides. Enjoy your milk/cheese/yogurt in moderation (2-3 servings per day) without a side of guilt/fear.
References
- Rodríguez-Alcalá LM, Castro-Gómez MP, Pimentel LL, Fontecha J. Milk fat components with potential anticancer activity-a review. Biosci Rep. 2017 Nov 15;37(6):BSR20170705. doi: 10.1042/BSR20170705. PMID: 29026007; PMCID: PMC6372256.
- World Cancer Research Fund/American Institute for Cancer Research. Continuous Update Project Expert Report 2018. Meat, fish, and dairy products and the risk of cancer. Available at dietandcancerreport.org
- Śliżewska K, Markowiak-Kopeć P, Śliżewska W. The Role of Probiotics in Cancer Prevention. Cancers (Basel). 2020;13(1):20. Published 2020 Dec 23. doi:10.3390/cancers13010020
- Nelson M. A Study Suggests Milk Increases the Risk of Breast Cancer, but AICR Experts Say Not So Fast. American Institute for Cancer Research. Published March 18, 2020. Accessed June 16, 2024. https://www.aicr.org/news/a-study-suggests-milk-increases-the-risk-of-breast-cancer-but-aicr-experts-say-not-so-fast/
This blog is not intended as medical nutrition therapy, medical advice, or diagnosis and should in no way replace consultation or recommendation from your medical professional.
