Dear Doctor: My wife of 40 years died seven months ago after a battle with cancer. Since then, I have been suffering from frequent bouts of depression, haunted by the loss of my life partner. During these episodes I can feel something like a mild form of an adrenaline rush. What is it? Should I be worried?

Dear Reader: We're deeply sorry for your loss, and for your struggle since then. Coping with the death of a beloved life partner is among the most difficult things we humans can face. At first, we're buffered by shock, which can confer a protective numbness. Then there's the whirlwind of activities associated with the ending of a life, which bring their own type of distraction and relief. It's afterward, when the world around us inevitably moves on, that reality sets in. And as you're experiencing, the effects are both emotional and physical.

Bereavement and grief can cause intense emotional experiences. Among them is depression, which can have physical manifestations like fatigue, muscle aches and pains, sleep disturbance, loss of appetite, headaches and digestive disturbances. Another common effect of profound loss is anxiety, which we think is also involved in the physical symptoms that you're describing.

To answer your second question, no, you don't need to be worried about these episodes. They are a natural part of the grieving process. Although your wife passed away seven months ago, your awareness of impending loss quite likely began with, or soon after, her cancer diagnosis. During the time of her illness, you were focused on her as her caregiver. Now, not only are you processing her death, you're also facing a radically altered life. That's a lot to take in, and it can send your nervous system into panic mode.

Unfortunately, there are no shortcuts for dealing with grief. Some people will find they are OK after a few months, while for others it can take several years to recover. The thing to know, and to explain to the well-meaning people who may tell you it's time to move on, is that there is no right or wrong way to grieve. It takes as long as it takes.

That said, there are several things that can make moving through this transition more bearable. First, take care of yourself physically. That means a healthy diet, moderate exercise and adequate sleep. Continue to make and keep all of your regular medical appointments and stay current on any medications you've been prescribed. When you're depressed or anxious, it can be all too easy to let the basics slide, yet the nuts and bolts of a day-to-day routine can be the solid ground on which you build your recovery.

Another important step is identifying a support system. If you have friends or family reaching out to you, please do reach back, even when you don't think you feel like it. A bereavement support group can offer you a place not only to feel less alone by sharing your grief, but it will also give you the chance to help someone else. And finally, please do talk to your family doctor. He or she can be a wonderful resource.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: I recently read an article that said even a little bit of weight loss -- just 5 percent of your total body weight -- can lessen your risk of breast cancer. Why is that? Does it hold true for women who are of normal weight?

Dear Reader: The link between being overweight and breast cancer risk is somewhat complex. Having more fat tissue is associated with higher levels of the hormone estrogen. This, in turn, has been connected to an increase in the risk of breast cancer. That extra weight can often result in higher levels of insulin, which has also been linked to an increase in breast cancer risk. Weight gain is also associated with a rise in inflammation, though whether this plays a role in cancer is still being studied.

Meanwhile, some research has connected this rise in breast cancer risk to excess weight that was gained in adulthood but finds that it may not apply to women who were overweight or obese as children. And to top things off, as these studies become deliberately more inclusive and diverse, it appears that ethnicity and race also play a role in whether or not excess weight adds to an individual's breast cancer risk.

The study you're referring to comes from City of Hope, a cancer treatment and research center here in Southern California. The impetus was to learn if weight loss might reverse the increased risk of breast cancer in women who were overweight or obese. The scientists also wanted to know whether the timing of that weight loss would matter.

They drew from data compiled by the Women's Health Initiative, a long-term study of health outcomes in older women overseen by the National Institutes of Health. The 61,000 women in the breast cancer study, all post-menopause, had normal mammograms at the start of the 11-year period of the study.

The researchers compared the health data of women who lost (and maintained the loss) of at least 5 percent of their total body weight with the health data of those whose weight remained the same. One of the takeaways, as you mentioned, was that the 5 percent weight loss was associated with a reduced breast cancer risk.

Unfortunately, this study doesn't answer your question about weight loss and a reduction of breast cancer risk among women who are not overweight. The women in the study who lost weight started out with an average body mass index, or BMI, of 29. That's deep into the overweight category, which is a BMI between 25 and 29, and bumping up against the lower threshold of obesity, which is a BMI of 30 and above.

However, body weight isn't the only factor to consider. The presence of abdominal fat, independent of body weight, has been linked with an increased risk of several types of cancer, including colon, rectal and pancreatic cancers. It's also a risk factor in a number of metabolic diseases.

Our advice is to reduce your weight and your middle with a healthful, whole-food diet and regular exercise. And, if you're regulars here, you pretty much know what's next: Please, no smoking.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: Our dad is a science geek, and his new obsession is the gut microbiome. But now he's telling anyone who will listen that the mouth microbiome is just as important as the one in the gut. Is that really true? Am I helping or hurting it when I brush my teeth?

Dear Reader: Kudos to your science-minded father, who is clearly staying current on the latest research. The oral microbiome, which according to most scientists includes the mouth and the associated nasal regions and cavities, turns out to be second in size only to the microbiome in our guts. It's home to more than 700 different bacterial species, as well as viruses, fungi and protozoa. That means it's one of the most densely populated anatomical sites in our bodies.

Studies have shown that different areas of the mouth and its associated areas, including the pharynx, esophagus, trachea, nasal passages, Eustachian tubes, middle ear and sinuses -- are colonized by microbial communities that are unique from one another. And thanks to stable temperature and moisture, a consistent food supply, and a pH range of 6.5 to 7.5, which hits the bacterial sweet spot, the oral-nasal cavity is the ideal bacterial environment.

Not only do these conditions allow the many millions (some say it's billions) of bacteria in the oral microbiome to thrive, the location itself means they are uniquely mobile. Thanks to saliva production and the vascular systems that keep our gums, tissues and nasal membranes healthy, bacteria from our mouths and noses wind up in the GI tract and in the bloodstream. The passage of air through the nose and mouth carries bacteria to the trachea and lungs. That places the various components of the oral microbiome into prime position to travel throughout the body. Not only are residents of the oral microbiome known to be responsible for conditions like morning breath, plaque and gum disease, researchers have established connections between oral bacteria and a variety of cardiovascular issues.

New research is now focused on exploring potential connections to outcomes as diverse as pregnancy complications, diabetes, respiratory diseases, various cancers and even certain neurological conditions like Parkinson's disease and multiple sclerosis.

In answer to your second question, no, you're not killing your oral microbiome when you brush your teeth. Please, don't stop brushing. And do continue flossing. Use a good toothbrush and practice proper technique. If you think that maybe you're doing either one wrong, your dentist will be happy to guide you.

Also, as science continues to decode the importance of the trillions of microscopic creatures we host in our bodies, the consensus is growing that antibacterial products are not a great idea. In our opinion, ditching the harsh and powerful kill-them-all antibacterial mouthwashes would be wise. Rinse with water, which with a pH of 7 matches the ideal environment in your mouth.

While in the future it's quite possible that dentistry will routinely include personalized treatments based on sampling the bacterial profile of a patient's mouth, right now we're limited to more traditional methods. The key is to actually use them.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)