Studies show that women with fewer than six friends have significantly higher rates of coronary artery disease, obesity, diabetes, high blood pressure and depression.

Here's how you can nurture these important relationships.

1. BE HER CHEERLEADER

Everyone gets down once in a while, so why not use your role as friend to boost your bud's confidence? When health and family writer Louise Gleeson, of Oakville Ont., first started her freelance business, one of her best friends had a box of beautiful customized business cards delivered to the door of her home. "She couldn't have cheered any louder for me if she had been standing at my door with pom poms," says Gleeson.

2. MAKE HER A PRIORITY

Set aside time for a weekly phone call, monthly movie night or even just an annual walk down memory lane, via your favourite teenage haunts. Dr. Irene Levine, PhD., is a professor of psychiatry at the NYU School of Medicine and an expert on friendships: she surveyed 1,500 women about their relationships for her book, Best Friends Forever (2009, Overlook Press). Dr. Levine's own best friend lives thousands of miles away, but, "we keep in regular contact. We cheer on each other's successes and are always available for a shoulder to cry on."

3. GIVE THE ADVICE A REST

Hearing my own debt-saddled friend lament his money woes one day, then describe his luxe new ride the next, is frustrating. But swooping in to fix his financial fiasco won't make everything better — and I know venting will help him work out things in his own mind. "The main thing is to set up some boundaries...and not to get sucked in as an enabler," says Dr. Levine. "Listen and, once in a while, give your opinion — but nobody wants to be harangued." So, unless his health or safety is an issue, I try biting my tongue and empathizing about how stressful his financial situation must be.

4. DON'T SPILL HER SECRETS

According to a recent study, six in 10 women can't keep their lips sealed and those who do blab are likely to do so within 47 hours. What to do when those natural impulses takes over? "Tell yourself it's not my information to share," says Marilyn Bellegham, M. Ed., a Burlington, Ont. relationship therapist. "I wouldn't want someone to take something I've said and share it!" If you know you're bad at staying mum, she advises asking your friend to leave you out of the loop.

5. DON'T JUDGE

After a seven-month struggle with nursing, Rachel Hoffman of Cape Coral, Fla. made the decision to stop breastfeeding. Looking for encouragement, she wrote about her disappointment in her Facebook status. While she did receive some messages of sisterly support, she was also bombarded with criticism from friends. Hoffman felt "hurt and attacked". (Needless to say, they're not on her list of friend's any more.) The bottom line: good friends know when to keep their opinions to themselves.

6. KNOW WHEN TO SAY WHEN

Good friends don't worry that he's only driven once and you've played chauffeur the past three times, but they don't take advantage either. If you're starting to screen your calls because a friend has been leaning on you a bit too heavily through her divorce, it's probably time to say something, says Dr. Levine. "If you feel yourself becoming resentful, you probably need to talk about it. People can't be everything to another person...you need to set some boundaries."

7. CELEBRATE HER SUCCESSES

When a good friend drops 30 pounds and looks fantastic, you might look down at your own bulging gut and mutter a snarky "must be nice!" "To be a good friend we also have to be a good friend to ourselves," says Bellingham. "If we have a good strong self image, we don't tend to say 'Oh, they can do something better than me!' we say 'Isn't that great! Look what she can do!'" Bite the head off that green-eyed monster by reminding yourself that you and your friend are two different people and focus instead on how great your friend is feeling.

8. CH CH CH CHANGES

"It means a lot when my friends understand life with kids sometimes gets in the way of friendships," says of Kathleen Clay, a Courtice, Ont. mother of three. "It's not that I don't want to get together, but, most days, my life is just not my own." If you're a new mom, try to let your friends know that even though you can't be there for them like you used to be, you still treasure them. On the other hand, if you're the one feeling slighted, try offering to babysit and supporting your friend in her demanding new role as mom, rather than making her feel guilty.