Every weekend, students indulge in colas that cover up the Captain, but these carbonated confections can have harmful effects.

A Tufts University study found women drinking three 12 oz. colas a day will have 5 percent less bone density than women who drink less than a serving a day. The study also looked at diet colas, which also decreased bone density by 5 percent.

According to a press release from Tufts' Friedman School of Nutrition Science and Policy, researchers believe phosphoric acid in cola drinks has a negative effect on bones. The excess phosphoric acid binds to calcium and prevents it from being absorbed, the press release said.

The study examined the bone density of more than 2,500 men and women and observed their soda consumption.

"If you're healthy and have a good diet you probably get enough calcium," JoAnna Moyer, clinical manager of women's health services, said. "But most college students are not getting enough."

Moyer said eating disorders or being really thin will encourage the body to lose bone when it is supposed to be building it.

There are some risk factors students can control to avoid losing bone mass, Moyer said.

Exercising makes bones and muscles stronger and can actually slow down the bone-loss rate, Moyer said.

"After early 20s, people start to lose bone, and how rapidly the holes get bigger vary from one person to another depending on lifestyle," Moyer said. "We can do weight-bearing exercise three to four times a week to avoid this."

Moyer said walking and jogging are two great exercises that may prevent loss of bone.

"Swimming doesn't do it though," Moyer said. "It's good for aerobics and heart health, but not to increase bone mass."

Making sure students eat a balanced diet is also crucial to avoid bone loss, Moyer said.

Vitamin D is essential to absorb calcium, Moyer said.

"You could eat and take all the calcium you want, but without vitamin D it will not be beneficial to you," Moyer said.

Most vitamin D comes from the sunshine, Moyer said.

"Everyone should have sunshine everyday," she added.

Moyer suggests eating plenty of fish, especially tuna and salmon, low-fat dairy products like cheese and yogurt, and drink plenty of milk and fortified orange juice to meet daily calcium requirements. She also encourages all students to take calcium supplementation every day.

Moyer said loss of bone density will eventually lead to osteoporosis, a disease which deteriorates bone.

Moyer compared bone to honey comb.

"A person who gets osteoporosis gets larger spaces within the honey and the connectors from inside the bone to the edge or border become thinner," she said.

"After you reach mid-20s, you stop storing and thickening bones and begin gradual bone loss," Moyer said.

Throughout college, students should be storing calcium and Vitamin D as a reserve for later in life, she said.

Major bone loss will not occur until menopause for women, though, Moyer said. "Within five to seven years of reaching menopause, women will lose 20 percent of bone mass," she said. "But if they start taking the necessary steps to build up a reserve, the effects of menopause will be less."

Women are five times more likely than men to develop osteoporosis because they have smaller and thinner bones and lose estrogen after menopause, Moyer added.