The following is an email conversation between one of our participants in the 30-Day Challenge, Carole and the Healthy Foodie. It's presented here so others participating in the challenge can get some helpful tips and advice. If you missed our other posts and want to follow the challenge, here are some resources to get you started:

Benefits of eliminating gluten, dairy, sugar, caffeine, alcohol and processed foods.
What you can and cannot eat
Getting started and getting off coffee
Recipe ideas and resources

Healthy Foodie: Hello Carole. How is everything is going. How are you finding the challenge?

Carole: I had told you that eliminating sugar would not be too difficult. Well, I am amazed at just how much hidden sugar I have been eating every day! Wow. From the dressing I put on my salad to the TV dinner (I know - not healthy) I often have for dinner. I am just amazed after checking out labels how much sugar there is in so many products. Your list of off-limit ingredients included avoiding fructose. Is that not the sugar found in fruit? This confuses me as I had thought that agave was a fruit nectar.

It's often touted by the holistic nutrition pundits that North America is a starving continent. It seems paradoxical that nations that have an out-of-control obesity problem could be said to be suffering from starvation, but there is logic behind the statement. With our nutrient-depleted foods coming from mineral-depleted soils, the over-processing of our foods and the artificial ingredients that replace real ingredients, the Western world is suffering from a starvation of nutrients!

In fact, it's reasonable to assume that this starvation is partially to blame for the obesity epidemic. People who eat nutrient-depleted food need to eat an excessive amount of it in order to satisfy the body's needs (although, it's usually a distended abdomen that stops a person from eating, not a true feeling of satiety). Ultimately, we eat excessive amounts of poor quality food in an effort to compensate for our cravings for nutrients and thus are gaining weight as a result.

A new study from the Journal of Cancer Research, supported by the US National Cancer Institute (NCI), published findings that show promise for the prevention of lung cancer. The study found that folate, multivitamins and green leafy vegetables may reduce the risk of lung cancer in current and former smokers.

The consumption of certain micronutrients may lessen a process called methylation, which has an effect on gene signaling. Since many genes in lung tumors, including those responsible for cell division and other significant cell processes, are methylated, researchers speculated that nutrients decreasing methylation may reduce risk of lung cancer.

The nutrients studied included a multivitamin rich in phytochemicals like vitamin C, carotenoids, lutein, folic acid, vitamin A and vitamin K. Researchers also showed that reduced gene methylation occurred with consumption of these micronutrients as components of green leafy vegetables.

Specifically, telomere length may set the limit for biological aging. Theoretically, any lifestyle change that affects telomere length also affects longevity. Previous studies have found that telomeres are highly susceptible to oxidative stress. This may explain how multivitamins are affecting the length of telomeres since multivitamin supplements represent a major source of micronutrient antioxidants which curb oxidative stress.

There has been some negative press associated with multivitamins lately, namely the claim that long-term use has no impact on the risk of cancer or heart disease and another report that warns of problems in the ingredients.

We asked the author of The Hormone Diet Dr. Natasha Turner whether we should be taking a multivitamin daily.

Read her response after the jump.

Each morning, we weigh in on the day's hottest headlines.

Despite all the controversy, I didn't see this one coming -- Madonna's adoption of little Malawian orphan Mercy has been denied. Poor Mercy -- how awful would it be to always know that you were almost adopted by Madonna?!

Taking the same multivitamin as your hubby? According to the LA Times, you might want to consider investing in gender-specific ones.

When you've got a migraine, the last thing you want to do is lace up your sneakers and head for a run. But according to recent research, that might just be the thing to help you work through the pain.

Another side effect of global warming? Allergy season comes quicker and lasts longer. Awesome.

I have a hard time picturing bubbly Reese Witherspoon hating anything, but apparently she absolutely loathes the gym.

Dear Dr. Roizen, With regards to vitamin supplements, do you think one multi a day does the trick?

Dr. Roizen: No, usually the multis don't have enough Vitamin D in it (you need at least 1000 IU a day), nor do they have enough calcium and magnesium: 600 mg calcium and 200 mg of magnesium twice a day is appropriate and those should be taken at least 2 hours separate from your multi as the vitamin C in the multi inhibits calcium absorption (and if you have iron because you are in a potentially pregnant era, that iron inhibits it as well), plus 600 mg DHA.

Dr. Michael F. Roizen is the chief wellness officer and chair of the Wellness Institute of the Cleveland Clinic. He is also the cofounder and originator of RealAge.com, and one of the author of YOU: Being Beautiful The Owner's Manual to Inner and Outer Beauty