Caffeine and fertility - find out about the world's most popular stimulant drug
The topic of caffeine and fertility is confusing for most!
Do you have an addiction to caffeine? Your not alone!
Caffeine's a substance found in an estimated 60-100 plant species worldwide and is a natural chemical found in the nuts, seeds, fruit, or leaves. This chemical acts as a pesticide for the plant and paralyzes or kills certain insects.
Around 80 percent of people worldwide consume caffeine in one way or another. It's popular because of its stimulant effects and is the worlds most used psychoactive substance!
Caffeine speeds up the action of the brain and heightens alertness. Other effects of this drug are tensing of the muscles, opening of the breathing tubes, and increased heartbeat. People enjoy the feelings and energy that this boost produces (especially in the morning to wake us up)!
However too much of a good thing can result in anxiety, insomnia, trembling, heart palpitations, increased urination, or diarrhea.
Consumption in the forms of coffee, tea, chocolate, cola, and energy drinks are the most well known. Some prescription or over the counter medications also contain this substance for its medicinal properties (headache preparations and some pain relievers). As popular as this product is, caffeine and fertility is a topic that should be investigated.
What are the health effects of caffeine with regards to fertility?
Many studies of caffeine and fertility levels have been performed around the world, and is still an ongoing topic of research and debate. Although studies have come up with very mixed results, most come to the conclusion that there's a negative link between caffeine and fertility.
There are several variables which may account for the different data reported on caffeine and fertility research (mostly coffee). Some of these include accuracy issues - large range of cup sizes, different beans, grinds and measurements, brewing methods, plus any other contributing lifestyle risk factors.
It's thought that caffeine consumption can cause delayed pregnancy, or lead to fertility problems for both men and women. Studies have also associated a link between caffeine and miscarriage with women.
Research - Men
✖ Guys, you may have heard rumors that a cup of coffee is good for your sperm? Under laboratory conditions, sperm has shown a short increase with the percentage of motile sperm when caffeine was added (in a dish)! However, looking at the bigger picture, the sperm motility decreased faster than normal over a period of time, which makes it harder to reach or fertilize the egg.
✖ The University of California/Berkeley (U.S.) and the Bradford University (UK) put together a report paper regarding a study done by their scientists regarding the consumption of caffeine on men's fertility. Their research findings were published online in the Journal of Human Reproduction - October 19, 2006.
A group of 80 men were tested, all normal and healthy (non smokers) ages ranging from 22 to 80. Results found the men who consumed greater than three cups of coffee per day had increased genetic damage to sperm, independent of their ages. The reason for this abnormality is not yet known. DNA damage increases the risk of offspring having developmental problems and genetic diseases.
Research - Women
✖ There have been several large studies reporting a definite connection between women's caffeine intake and delayed conception. One American study found that the risk for not conceiving for 12 months was 55% higher for women who consumed only one cup of coffee per day! On the other hand, some studies on caffeine and fertility have not been able to find any steady correlation between the two.
✖ Dr. Daniel W. Cramer from Brigham and Women's Hospital in Boston, Massachusetts (U.S.) was the lead author of a study on caffeine and fertility for women. Caffeine intake was linked to higher estrogen levels. The study included nearly 500 women aged 36-45 who were not pregnant, breast feeding, or taking hormones. Those who consumed at least 500mg of caffeine per day had nearly 70% more estrogen during their early follicular phase of their menstrual cycles (compared to women who consumed no more than 100mg of caffeine daily). Published in Fertility and Sterility - October 2001, volume 76, issue 4, pages 723-729.
Raised estrogen levels are responsible for many reproductive disorders and can contribute towards infertility. Endometriosis feeds off estrogen, so any female that has this condition needs to definitely cut back on caffeine.
✖ If a woman does become pregnant, caffeine can cross through the placenta into the embryo/fetus. Most women don't know that they are pregnant during the first few weeks, so therefore it's best keep caffeine consumption low if you are trying to conceive.
A study was conducted on 1,063 pregnant women regarding caffeine consumption and miscarriage, which was published in the Journal of Obstetrics and Gynecology - published online January 21, 2008. The lead author was Dr De-Kun Li, a reproductive perinatal epidemiologist at the Kasser Permenente Division of Research in Oakland (California U.S.).
The study found that pregnant women who consumed 200mg or more of caffeine per day, had twice the risk for miscarriage than women who consumed no caffeine. There were no other known contributing risk factors involved within this research.
The women who had no caffeine intake, had a miscarriage rate of 12.5%. Women who consumed 200mg+ of caffeine per day, had a miscarriage rate of 24.5%.
Other studies from various sources claim the higher the caffeine consumption, the higher the risk for miscarriage. There have also been links to high caffeine consumption (more than three cups coffee per day) in the month before pregnancy, with an increased risk for miscarriage.
✖ Research has also shown that consumption of too much caffeine can substantially reduce the body's ability to absorb iron. This is an important nutrient needed for supporting female fertility. Several studies indicate that lowered iron levels can contribute towards ovulation disorders. Therefore this is one area where caffeine and fertility issues may have an inter-connection, but unfortunately this fact is often overlooked.
There's also believed to be a relationship between women's iron deficiencies and stillbirth. As it's not uncommon for women to suffer from a lack of iron, it would pay to have your levels checked. This is especially the case if you're a moderate to heavy coffee/tea drinker. You can do this via a simple blood test (easy)! Your doctor will prescribe an iron supplement if necessary.
How are caffeine and fertility problems connected together?
Good question, but scientists are still trying to find out all the causes! They're still far away from fully understanding all of the reasons. It's thought that caffeine has several different effects on the functioning/regulation of our sex hormones. There are several different opinions as to why.
Caffeine stimulates the adrenal glands which causes the release of adrenalin hormones. This in turn causes the liver to release glucose (sugar from carbohydrates) into the bloodstream, and this provides energy. This is the buzz!
One common theory is that the intake of caffeine gives insulin a higher resistance to changes in blood sugar levels. This is referred to as insulin resistance. Insulin regulates the blood sugar levels in the body. Increased amounts of this hormone are then produced to help stabilize the blood sugar.
Studies suggest that this increased insulin process contributes towards other hormonal irregularities, and has implications with regards to our reproductive health.
This insulin resistance can cause a drop in sperm production in men, and women may not ovulate.
Caffeine and fertility problems can be a particular issue for people who may already have insulin resistance related medical problems, such as obesity or diabetes. Women with (PCOS) should also be especially wary of caffeine.
Caffeine has a diuretic effect, which makes us pass more urine than normal. This in turn, can flush out important nutrients that are essential for the reproductive system to function at an optimal level.
The amount of time it takes for an adult to metabolize caffeine out of their system varies greatly. Statistics claim anywhere from six to ten hours for a healthy non smoking adult, to a few days for someone with an extra slow metabolism. Here's a couple of interesting facts regarding caffeine and fertility - women who are on the contraceptive pill or who are ovulating, can take twice as long for their body to eliminate the caffeine! Pregnancy makes this elimination time longer again.
How much caffeine is safe for fertility?
This also varies with recommendations, but with so much negativity associated between caffeine and fertility, caution is the key. Women are advised to not go over 150mg per day. This is in case a pregnancy occurs. Light to moderate consumption for men is considered to be safe (under 300mg but less than 250 is best). Beware that there's a fine line with amounts because it's extremely difficult to know exactly how much we may be ingesting!
If you decide to give up coffee for a while, wean yourself off slowly, to cut down on withdrawal symptoms (most commonly headaches)!
How much caffeine in coffee and tea?
One espresso shot (1 fluid ounce) of coffee on average is around 100mg. This can vary depending on how the beans are produced, level of the grind and the amount of water/coffee ratio.
Drip coffee - 110 to 165mg per 5 ounce cup or 140ml (most common coffee measurement)
Percolated coffee - 64 to 134mg per 5 ounce cup
Instant coffee - between 40 to 108mg per 5 ounce cup
Decaffeinated coffee - between 2 and 5 mg per 5 ounce cup
Black tea (loose leaf) - 25 to 110mg per 8 ounce cup or 225ml (most common tea measurement)
Oolong tea (loose leaf) - 12 to 75mg per 8 ounce cup
Green tea (loose leaf) - 8 to 70mg per 8 ounce cup
White tea (loose leaf) - 6 to 55mg per 8 ounce cup
Tea bags - check packaging for exact caffeine measurements
Dark chocolate bar (average) - 30mg per 1.5 ounce or 43 grams
Milk chocolate bar (average) - 10mg per 1.5 ounce or 43 grams
Coca Cola - 34mg per 12 fl oz or 335ml
Red Bull (energy drink) - 80mg per 8.2 fl oz or 250ml
*Please note - These coffee and tea figures have been taken from numerous sources, and we've shown the most common figures. As you can see, it's near impossible to know the exact caffeine amount as different factors can alter the measurements. Therefore we suggest to presume the higher numbers if you are counting your daily amounts!
Make sure you start looking at product packaging labels to see what the caffeine content is.
Don’t forget investigating caffeine levels in any medication you may be taking.
*Note about tea - Tea contains a substance called tannin. Don't drink tea with your meals, as tannin inhibits the body's ability to absorb non-heme iron (from plant sources).
If you're thinking about trying for a baby, you first need to consider the health effects of caffeine on your reproductive system. The relationship between caffeine and fertility is just one of the issues that may affect your odds, so now is the time to do something about any other bad habits you may have.
Have a look at our page on preconception care as this has good information for guys and gals regarding ways to optimize our fertility health. A detoxifying time for both prospective parents is highly recommended. After all, you only want to ensure the healthiest possible start for your unborn child! Both partners being in tip top shape can minimize the risk of pregnancy complications, or any birth abnormalities.
Remember ladies that once pregnant caffeine can be passed onto your baby through breast feeding.
So the conclusion here regarding caffeine and fertility is, to keep the caffeine consumption minimal (just to be safe) before and while you are trying to conceive. Still enjoy your morning cuppa, or leave the coffee for a treat now and then!