According to the U.S. Centers for Disease Control and Prevention (CDC), 5 to 20 percent of Americans contract the influenza (flu) virus each year. Flu produces a spectrum of disease, ranging from mild, self-limited respiratory disease to life-threatening pneumonia.

Trying to get your body to conform to a particular shape can be a losing proposition as body ideals change from decade to decade. Contrast the curvy 1950s with the skinny 1960s, and you can see how the body image that was ideal before suddenly fell out of fashion.

While it might feel awkward and could throw off your balance, bending over in the last three months of pregnancy will not hurt you or your baby in any way. Your baby is well protected by the abdominal wall and muscles, the uterine wall -- which is also composed of muscle -- and the amniotic fluid around him.

Trace minerals are a type of mineral essential to your body for optimal health but not required by your body in large quantities. Specifically, trace minerals support immune system function, energy, metabolism and antioxidant protection.

Iodine is an essential mineral found in seafood, iodized salt and some fruits and vegetables. Excess iodine is normally removed from your body by your kidneys. However, if your kidneys are unhealthy, iodine may build up in your body, resulting in iodine toxicity.

Milk thistle is a prickly composite herb from the Mediterranean region and has been used extensively in traditional folk medicine to treat liver and gallbladder diseases. This traditional use has also been validated by modern clinical research. Milk thistle is also taken to shrink gallstones and remove bladder pain.

Food poisoning from eating undercooked pork often comes from meat that was already infected with parasitic organisms or contaminated with bacteria during slaughter, processing or preparation.

Creatinine comes from your body's everyday use of your muscles -- and also from eating meat. As blood flows through the kidneys, creatinine is excreted out into your urine along with other waste products.

Dark spots may be referred to as liver spots, age spots, pigment spots or brown spots. According to MayoClinic.com, these spots are harmless, but they may look like cancerous growths. In addition, they also state that these spots most commonly appear in adults over the age of 40; however, they may affect anyone.

While your weight can be a reflection of your current state of health, your height usually isn't. According to "Scientific American," 20 to 40 percent of your height is determined by environmental factors like nutrition, but 60 to 80 percent is determined by genetics.

New discoveries about how the body's systems function and work together continue to emerge almost daily. However, a very basic and fundamental understanding of the body's integrated working parts and organ systems has been in place for centuries.

Blood sugar, or glucose, serves as the fuel your body uses to generate energy. The level of glucose in your blood remains fairly stable, slightly rising after eating and declining a small amount between meals or after exercising. Blood glucose can be measured in many ways.