Twinning is Sometimes a Family Affair

   Statistics vary but about one in every ninety births in the United States are twins, and sometimes the propensity to have twins can run in families. There are two main types of twins, identical and fraternal. Identical twins occur when a single fertilized egg splits in two, usually before the eighth day of development. Each then develops into two separate but genetically identical embryos. Heredity and family history seem to play no role in the occurrence of identical twins.  

   Nutrition may also increase the odds of having fraternal twins. The highest rates of fraternal twinning in the world are found in certain parts of West Africa where a lot of cassava is eaten. The peel of this potato-like root is thought to contain a substance that causes women to hyper-ovulate.

-Sean Kenniff, MD

Pregnancy is Possible Any Time of the Month

   For many women, having sexual intercourse during menstrual bleeding carries a lower risk of conception than having sex during mid-cycle. But it is still quite possible to become pregnant during menstruation for several reasons.

   Most women ovulate during mid-cycle, around days 12-16 of a 28-day cycle. But some women, especially teenagers and young adults, have irregular ovulation. The egg for the following cycle can be released from the ovary during menstrual bleeding or a few days afterward. Since sperm can survive for five days or longer in the uterus that egg can be fertilized.

   Women with shorter menstrual cycles (21 days) and longer periods (7-days) may be most at risk for conceiving during her period. Women often mistake other causes of vaginal bleeding with menstrual bleeding and sexual activity results in pregnancy. In fact it’s normal for some women to ‘spot’ or bleed a little during ovulation-the most fertile time of the cycle.

   The best way to prevent pregnancy is of course through abstinence and the judicious use of contraceptive devices and drugs. Birth control pills are very effective, but condoms have an added benefit. Some studies have show the risk of transmitting and contracting a sexually transmitted disease is increased during menstrual bleeding. -Sean Kenniff, MD

Does I.Q. Decline with Age?

   Though there is some evidence that the Intelligence Quotient (IQ) can increase during early childhood, it is supposed to remain relatively constant during adulthood. But the reason for this constancy is purely statistical and not biological.

   There are several different kinds of IQ tests and all of them are imperfect, but they are believed to provide a rough measure of a person’s reasoning ability. An IQ of 90-110 is considered average. After testing for verbal skills, visual-spatial abilities, mathematical reasoning and memory, a person’s raw score is calculated.

   This raw score is corrected for age, and then plotted on a bell curve against the scores of similarly aged people in the general population. In other words, IQ is not only a calculation, it is a comparison to other people of the same age. So, theoretically, a person of any age should always fall into the same percentile when compared with their peers.

   While one’s IQ may stay the same, most people do show a modest decline in mental performance on IQ testing as they age. Verbal skills seem to be retained the longest, but memory, mathematical ability and visual-spatial reasoning start to decline slowly around and 35, and more considerably after age 65. -Sean Kenniff, MD

Positively Poppy? Can Poppy Seeds Sway a Drug Test…

   People who are required to undergo random on-the-job drug testing often avoid poppy seeds because they fear they could lead to a positive drug test result. Though most poppy seeds sold commercially in the United States pose no risk during a routine drug test, some poppy seeds can contain trace amounts of opiates. If ingested your urine could test positive for drugs like morphine, codeine and heroin.

   Several studies have shown opiate levels in the urine rise within two hours of poppy seed ingestion, and can remain elevated for a day or two afterwards. If eaten with geat regularity the presence of opiates can be a bit higher and a bit more persistent. But since the levels found in poppy seed ingestion are generally lower than those found in drug use, many governmental groups and private corporations have simply increased the opiate level that is needed to be declared positive. This has eliminated a lot of the false positives due to poppy seeds.  

   Additionally the compound thebaine is found in the urine of people who have consumed poppy seeds but is not found in those who have been using opiate drugs. And more sophisticated drug testing techniques can now detect specific opiate drug byproducts.-Sean Kenniff, MD

Does ‘Carb-Loading’ Improve Athletic Performance?

  For generations, endurance athletes have practiced ‘carb-loading’, consuming large amounts of carbohydrates the night before the competition. Studies have found several different carb loading strategies can give athletes a competitive edge.

  During digestion carbohydrates are rapidly turned into glucose, a sugar that is the body’s primary and most immediate energy source. Excess glucose is then stored in the liver and muscles as glycogen. About four hours after a meal, the glycogen in the liver begins to break down and supply the body with glucose, but the glycogen in the muscle is reserved almost exclusively for muscle activity. By eating a high carbohydrate meal the night before a competition, athletes maximize the glycogen stores in their muscles, ensuring that the muscles will have enough glucose for strenuous activity.

  Studies have shown carb-loaded athletes perform better and their muscles do not fatigue as easily. However it is important to watch your calories. Excess calories of any kind have been shown to impair athletic performance. -Sean Kenniff, MD

Breast Cancer Risk: Does Size Matter?

 Large-breasted women are often concerned they could be facing an increased risk of breast cancer. Conversely, smaller-breasted women often assume they have less of a risk. But studies have shown there is no clear association between breast size and the risk of developing breast cancer. 

 The breast is primarily made up of two types of tissue: glandular tissue like the milk ducts and the mammary glands, and stromal tissue like fat and fibrous tissue. Breast cancer tumors usually arise from the glandular tissues. And while larger breasts can contain more glandular tissue than smaller breasts, breast size is largely a reflection of the amount of fatty tissue in the breast. Though some studies have shown a weak correlation between large breasts and breast cancer, most studies have not. 

 However there is some evidence that breast density could be a risk factor for breast cancer. Denser breasts have relatively less fatty tissue and more glandular tissues. While it is normal for young women to have dense breasts, many studies suggest women with increased breast density after menopause could be at a slightly increased risk of developing breast cancer. 

 It’s important to note that overweight and obese women often have larger breasts, and they also have a higher risk of breast cancer. But this is probably not related to increased breast size, but rather to the excess estrogen produced by fat cells in the body. -Sean Kenniff, MD