*stands up bravely* Hi, my name is Scicurious, and I'm a...caffeine addict.
Well, currently I'm a recovering caffeine addict. I used to drink about 6 cups of coffee a day. The big travel mug size. I was even in a caffeine study where they needed high users, and they were shocked by my intake. It started out as just a latte every once in a while, and then...it became my life. Caffeine was my molecule, my totem. I had a tshirt and everything. But a couple of months ago I got sick of myself. And I went decaf.
I've been clean most days for the past 8 weeks, with relapses for long car drives and when I have to give presentations. So far, I've actually noticed that I have improved attention off caffeine. I'm much more successful at making myself stay awake in meetings, never having to fight the inevitable crash. And I'm less nervous. The real goal is not to kick a bad habit. Rather, it's to try and decrease my tolerance to caffeine, so when I really need to it to write my thesis, I won't have to drink enough to make me paranoid.
So what does this have to do with boobs? Breasts? Titties? Cans? Jugs? I'm sure you can think of even more euphamisms. But what exactly does coffee have to do with my mammary glands?
Jernstrom et al. "Coffee intake and CYP1A2*1F genotype predict breast volume in young women: implications for breast cancer" British Journal of Cancer, 2008.
I will begin this with a little disclaimer. I know not a lot about breast cancer. Neither do I know a lot about gene regulation of cancer. So if I say something in my interpretation of this article which turns out to be incorrect, please call me on it and correct me. Better for us all to learn what is real and right, and my ego can always use some smackin'.
Now obviously, we can't grow and shrink ourselves, or various parts of our anatomy, by eating or drinking random things. In general, when we grow, we grow everywhere, and when we shrink, we shrink everywhere. Except when it's elephantitis... But normally, we are not Alice.
Though it might be fun to be Alice.
And in general, mammary gland size is determined by a combination of genetics and hormones. You are exposed to hormones produced by your body, and potentially from outside sources as well. But generally, if your mom has relatively small breasts, you will, too. If your mom has (natural) breasts so big she topples over when not properly supported, beware.
But getting on to the study. What's beautiful about this study is that it shows a combination of genes and environment affecting your body. Basically, there are various genes and alleles in your body connected with both breast size and breast cancer risk. In this study, they were looking at the CYP1A2*1F gene, a gene that by itself may not regulate breast size or breast cancer, but is linked to other genes that do, and is often used as a marker for breast cancer risk. If you have the A/A allele version of this gene, you're at lower risk for breast cancer than if you have the C-allele. The CYP1A2 gene is associated with breast size and density. It has also been noticed that women with larger breasts could be at higher risk for breast cancer (Kusano et al, 2006).
So why look at coffee? Some studies, though by no means all (Baker et al, 2006; Nkondjock et al, 2006; Ganmaa et al, 2008) have noticed a link between coffee intake and protection against breast cancer. Coffee contains more than just caffeine, it also contains chemicals called phytooestrogens, which can interact with your native estrogen receptors, potentially blocking them. Additionally, caffeine itself is metabolized by the CYP1A2 gene. The scientists reasoned that there could be some interactions here.
So they surveyed a whole bunch of women, looked at their breast size and density, and how much coffee they drank. They found that women who drank a lot of coffee (only 3+ cups per day, wusses), had lower breast volume that women who didn't drink as much. But this was ONLY if the women had the relatively risky C-allele for CYP1A2. This difference disappeared in women with the A/A allele, and in women who were on oral contraceptives (which play with your hormone levels).
Of course, coffee-induced activation of CYP1A2 only accounts for about 4% of its total activity, so other things could definitely be at work here. It could be the prolonged exposure to the caffeine itself, which is known to inhibit some kinds of cell growth (Hashimoto et al, 2004). There could be interactions with other hormones, like testosterone. But still, if you think you're at risk, or even if you're not, this is a good excuse to grab that morning latte. I want my coffee back!!
H Jernström, M Henningson, U Johansson, H Olsson (2008). Coffee intake and CYP1A2*1F genotype predict breast volume in young women: implications for breast cancer British Journal of Cancer, 99 (9), 1534-1538 DOI: 10.1038/sj.bjc.6604687
Baker JA, Beehler GP, Sawant AC, Jayaprakash V, McCann SE, Moysich KB (2006) Consumption of coffee, but not black tea, is associated with decreased risk of premenopausal breast cancer. J Nutr 136: 166-17
Nkondjock A, Ghadirian P, Kotsopoulos J, Lubinski J, Lynch H, Kim-Sing C, Horsman D, Rosen B, Isaacs C, Weber B, Foulkes W, Ainsworth P, Tung N, Eisen A, Friedman E, Eng C, Sun P, Narod SA (2006) Coffee consumption and breast cancer risk among BRCA1 and BRCA2 mutation carriers. Int J Cancer 118: 103-107
Ganmaa D, Willett WC, Li TY, Feskanich D, van Dam RM, Lopez-Garcia E, Hunter DJ, Holmes MD (2008) Coffee, tea, caffeine and risk of breast cancer: a 22-year follow-up. Int J Cancer 122: 2071-2076
Kusano AS, Trichopoulos D, Terry KL, Chen WY, Willett WC, Michels KB (2006) A prospective study of breast size and premenopausal breast cancer incidence. Int J Cancer 118: 2031-2034
Hashimoto T, He Z, Ma WY, Schmid PC, Bode AM, Yang CS, Dong Z (2004) Caffeine inhibits cell proliferation by G0/G1 phase arrest in JB6 cells. Cancer Res 64: 3344-3349