Dear Doctor: I love salty foods, always have, and I don’t have high blood pressure or heart disease or anything like that. But I did see a story recently that said high-salt diets can affect the brain. How worried should I be?

Dear Reader: Our attraction to salt -- researchers refer to it as “sodium appetite” -- has long fascinated everyone from scientists to philosophers to poets. At a physiological level, our bodies require sodium, which plays a key role in fluid balance, and in nerve and muscle function. As cooks (and eaters) know, adding salt to almost any food makes it taste better. And scientists in Australia recently identified specific pathways in the brain’s emotional center, which light up when salt is consumed, a reward system of sorts.

Yet as your question acknowledges, and as research has shown, too much salt in the diet puts you at risk of high blood pressure and heart disease. Now, a recent study from Weill Cornell Medical College, the research unit and medical school of Cornell University, has added the potential for cognitive impairment to woes caused by too much dietary salt.

When scientists fed mice a high-salt diet, the flow of blood to their brains declined, and the vessels that carried that blood were adversely affected. The mice also began to perform poorly on cognitive tests that, before this change to their diets, they had aced. What was particularly interesting was that, rather than this decline arising from a spike in blood pressure, it appeared to be tied to chemical changes in the brain that were prompted by an immune response in the gut. When the mice were returned to a normal diet, they regained the cognitive ground that they had lost. Whether this same scenario will translate to humans is not yet clear.

As for your own sodium consumption, we believe that even absent physical symptoms like high blood pressure, overdoing it with salt is not a good idea. And if you don’t really know how much salt you’re eating, then you’re like the majority of Americans. That may be why, according to the American Heart Association, most adults consume more than 3,400 milligrams of sodium per day, which is 30 percent more than the organization’s recommended maximum of 2,300 milligrams per day. A whopping 70 percent of that sodium comes from prepared and packaged foods and from restaurant meals. The rest comes out of the salt shaker.

We think it would be wise for you to begin to keep track of your daily sodium intake. Packaged and processed foods will have the numbers you need on their nutritional labels. To be accurate, be sure to pay attention to serving size as well. As of May 7, restaurants with 20 or more locations have been required by the Food and Drug Administration to provide customers with a range of nutritional information, including calorie counts and sodium content. And if you’re a home cook, track the sodium levels -- both in the ingredients you’re using as well as the salt you’re adding. Your body and maybe even your brain will thank you.

(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: What is sick sinus syndrome? Is a pacemaker the only cure? My grandmother was just diagnosed with it but, at age 94, has refused to even consider a pacemaker.

Dear Reader: Sick sinus syndrome refers to a problem with the sinoatrial node, or SA node. This is an area of highly specialized cells that controls the heart rate. Located in the right atrium, which is the upper right chamber of the heart, the SA node produces electrical impulses that start each heartbeat. When someone has sick sinus syndrome, it means that the SA node, the heart’s intrinsic pacemaker, is not functioning properly.

Either the signals it’s sending are erratic, or the impulses are disrupted and don’t reach the rest of the heart. In someone with sick sinus syndrome, the heartbeat is often too slow, which is known as bradycardia. The condition may also cause tachycardia, which is a heartbeat that is too fast. In some individuals, the heart will cycle between rhythms that are too slow and too fast. The condition can also be marked by long pauses in which the heart remains still as beats are skipped altogether. And while the SA node directly controls only the start of each heartbeat, due to the way the heart’s electrical system is interlinked, a malfunction disrupts the optimal functioning of all four of the chambers of the heart.

Not everyone experiences symptoms as a result of the condition. When they do occur, they can include feeling lightheaded or dizzy, which can sometimes lead to fainting. There may be a fluttery sensation in the chest, or a feeling of pounding heartbeats. Because the condition prevents optimal blood flow, it can result in fatigue, memory problems and confusion. It will also often lead to problems during exercise or exertion, such as chest pain or labored breathing. Although sick sinus syndrome can occur at any age, it is most common among the elderly and is believed to be the result of age-related changes to the heart.

There is no known cure for sick sinus syndrome. For most individuals with the condition, a pacemaker is eventually needed to regulate the heartbeat. This is a medical device that is surgically implanted in the chest and, through the use of sensors and electrical pulses, monitors and then regulates the heartbeat. The sensors let the pacemaker know when the heart’s rhythm goes awry, and the device then sends an electrical pulse to prompt the heart back into a normal rhythm.

The type of pacemaker a patient needs depends on the type of heart irregularity he or she has. The technology has been advancing, with the newest pacemakers now the size of a nickel. It’s estimated that sick sinus syndrome -- which is found in 1 out of every 600 cardiac patients over the age of 65 -- is the reason behind at least half of all pacemaker implants in the United States.

Regarding your grandmother’s refusal of a pacemaker, it’s not unusual of people of advanced years to say no to medical interventions. The most you can do is make sure she fully understands the potential benefits and risks of the device.

(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: When our dad gets sick, he pretty much collapses into bed for a few days. My mom teases him and calls it the “man flu.” To us kids, it’s a family joke, but a friend insists man flu is real. Is she right?

Dear Reader: We’re talking about “man flu” because Dr. Kyle Sue, an assistant professor at Memorial University of Newfoundland in Canada, got tired of being labeled a drama queen when he was laid low by a respiratory infection. According to the definition -- and, yes, it’s common enough to have made it into both the Oxford and Cambridge dictionaries -- man flu is “an illness such as a cold that is not serious, but that the person who has it treats as more serious, usually when this person is a man.”

The takeaway is that when it comes to getting sick, men can be wimps. But as Sue points out, the assumption that a man with the flu is exaggerating his symptoms and discomfort can inadvertently lead to improper or insufficient medical care. To that end, Sue set out to study man flu. He sifted through various scientific databases using keywords that would cull research related to viral respiratory illnesses and their outcomes in both women and men.

What he found was that, perhaps due to certain physiological differences between the sexes, a man’s immune system appears to react more forcefully to the influenza virus than a woman’s. That may sound like a good thing, but the aches, pains, fever, chills and outpouring of mucus that typically accompany the flu are all courtesy of your immune system’s best efforts. A stronger immune response means worse symptoms.

The differences begin in the test tube. Nasal cells from both women and men were infected with the influenza virus. When the women’s cells were exposed to estradiol, a female hormone, the immune response was more moderate. When the men’s cells were exposed to the same amount of estradiol, the hormone had no effect on the level of the immune response, which was more robust. When it comes to the flu vaccine, the protective antibody response in women appears to be better than in men. One theory links this to testosterone, as men with higher levels of the hormone produced fewer flu antibodies. So even despite a flu shot, a man may still get sick. Other studies that tracked flu-related hospitalizations and deaths found men represented in higher numbers than women. As to the evolutionary advantage to what Sue calls the “immunity gap,” he said more study is needed.

The fact is that in a number of diseases and conditions -- including heart disease, osteoarthritis, urinary tract health, stroke, migraine, alcoholism and mental health issues -- women and men are affected differently. As for Sue, even as he calls for more research into the subject, he closed his paper with his tongue firmly planted in his cheek:

“Perhaps,” he wrote, “now is the time for male-friendly spaces, equipped with enormous televisions and reclining chairs, to be set up where men can recover from the debilitating effects of man flu in safety and comfort.”

(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.)