Vitamin D plays a crucial role in calcium absorption and bone health. Because we get most of our vitamin D from the sun, many people develop an insufficiency in the colder months. For older women at risk for osteoporosis, it is vital to ensure you are getting enough of this nutrient.

In this Q&A, Christopher Anthony Gold, DO, Assistant Professor, Medicine (General Internal Medicine), Icahn School of Medicine at Mount Sinai, explains why vitamin D is important and how to make sure you are getting enough.

Why is vitamin D important?

Vitamin D helps calcium absorb into your bones, which keeps them strong and healthy. This prevents bone diseases like osteoporosis, especially in menopausal and postmenopausal women. Vitamin D plays other important roles, such as assisting with your immune system and muscle function, and protecting the brain and central nervous system. It has some anti-inflammatory effects, and there is some small evidence that suggests high levels of vitamin D may decrease your risk for insulin resistance, potentially decreasing your risk for prediabetes or diabetes.

How much vitamin D do I need?

Vitamin D deficiency is not as common in the United States, though some studies suggest up to 25 percent of certain patient populations can be deficient. Vitamin D insufficiency, however, is more common, and can be seen in up to 30-40 percent of the population in some studies. To prevent this, the National Academy of Medicine recommends getting at least 600 international units (IU), or 15 micrograms (mcg), a day for adults under age 70, and 800 for those over age 70, through sun exposure, food, and/or supplements. If you live in a region with less sunlight, you should get at least 600 and up to 1,000 IU (15-25 mcg) of vitamin D a day. Menopausal and postmenopausal women should aim for at least 800 IU (20 mcg) a day and should pair vitamin D with 1,000 to 1,200 milligrams of calcium.

Keep in mind that too much vitamin D can lead to toxicity, but this is rare. The safe upper limit is defined as 4,000 IU a day (100 mcg).

What causes vitamin D insufficiency?

Lack of sunlight is the main cause in most cases. It can also be caused by not getting enough vitamin D-rich foods and supplements, especially in the winter. Aging also increases your risk because your skin has more difficulty synthesizing vitamin D from sunlight as you get older. Certain medical conditions, such as obesity, also increase your risk.

What are the symptoms of vitamin D insufficiency and deficiency?

Many people with vitamin D insufficiency do not have any symptoms, but some people may experience muscle weakness, bone pain, and fatigue. These could be signs that you have developed a vitamin D deficiency, which leads to bone disorders.

Who is most at risk?

Those most at risk include:

• Older people
• People with darker skin
• People who live in northern regions with less sunlight
• People with obesity
• People who spend a lot of time indoors
• People with certain medical conditions, such as osteoporosis, hyperparathyroidism, celiac disease, and inflammatory bowel disease

One serving of wild salmon meets the daily requirement of vitamin D for most adults under age 70

How can I make sure I’m getting enough vitamin D, especially in the winter?

The National Institutes of Health suggests getting 5-30 minutes of sun exposure a day between 10 am and 4 pm without sunscreen. Keep in mind that getting too much sun can damage your skin and increase your risk for skin cancer.

In terms of diet, there are foods that are naturally higher in vitamin D. These include fatty fish, such as salmon, tuna, and mackerel. One serving of wild salmon—about three and a half ounces—contains about 600 IU, or 15 mcg, of vitamin D, which meets the daily intake requirement for most adults under age 70. Other sources include mushrooms and eggs, especially in the yolks. Some foods are supplemented and fortified with vitamin D in the United States, including milk, orange juice, yogurts, and some cereals. In terms of supplements, vitamin D2 and D3 are both great. Some research suggests that vitamin D3 may be a little more beneficial.

What should I do if I suspect my vitamin D levels are low?

If you suspect you are insufficient in any nutrient, you should talk to your primary care provider.

You may have heard lately about magnesium—from magnesium sprays to magnesium oils and other supplements that claim to reduce anxiety and help you sleep, among other health benefits. While the best way to get enough magnesium is to eat a well-balanced diet, supplements may help some people. However, there may be risks associated with these products, especially if you are taking them without guidance from your health care professional.

Jeffrey Mechanick, MD

In this Q&A, Jeffrey Mechanick, MD, Professor of Medicine and Medical Director of the Marie-Josée and Henry R. Kravis Center for Cardiovascular Health at Mount Sinai Fuster Heart Hospital, explains how to ensure you are consuming enough magnesium and what to do if you think you need supplements.

What are the benefits of magnesium?

Magnesium has multiple benefits. It is an electrolyte (a mineral like sodium and potassium that your body needs to function properly) used in almost all the cells in the body to help cells communicate and function. It improves energy; bone health; muscle contraction and function; neurologic function, including sleep and mood; and cardiovascular and gastrointestinal functions, such as blood pressure and the movement of food through your digestive system. Magnesium also reduces anxiety, headaches, and depression, and it improves and relieves premenstrual syndrome and postmenopausal symptoms.

What are the symptoms of magnesium deficiency?

The symptoms can include fatigue, muscle weakness, loss of appetite, nausea, headaches, constipation, chest pain, numbness or tingling and muscle cramps, and abnormal heart rhythms. In severe forms, magnesium deficiency may cause seizures, alterations in mood, and even subtle changes in your personality.

What are best ways to get more magnesium?

The best and safest way to get magnesium is from eating a well-balanced diet. As with all nutrients found in certain foods, magnesium is a micronutrient, meaning the body requires it in small amounts. Magnesium can be found in leafy green vegetables; certain types of beans, lentils and nuts; dairy products; dark chocolate; grains, such as brown rice and oatmeal; and some fruits, especially bananas, blackberries, and avocados.

Are magnesium supplements safe?

My response to this question is the same for all supplements—you should seek guidance from a health care professional before taking them. When it comes to dietary supplements, you need to be concerned about the product and whether it really contains any of the supplement or is adulterated. This could mean it contains other compounds that can lessen or mimic the effects of the active ingredient, since the supplement industry is a competitive market selling these products. It could also mean the product contains a hazardous substance that is a contaminant from the manufacturing process.

That said, a number of my patients say magnesium helps them sleep better, has helped with premenstrual syndrome and postmenopausal symptoms, or reduces their anxiety. If you take it in small amounts and you are taking the supplement under the guidance of a health care professional, it should be safe.

What can happen if I take too much magnesium?

If you take too much magnesium, you can develop a toxicity state, which can cause low blood pressure and diarrhea, among other problems. If you are healthy and eating well, you probably do not need a magnesium supplement. The exception could be if you are a high performance athlete or have a particular condition, such as an illness or vitamin D deficiency that causes your magnesium to be low.

How much magnesium should I take?

You should not take more than 350 to 400 milligrams of magnesium per day. You can look at the labeling to see how much is in one tablet or capsule. If there is any confusion, talk with your doctor or pharmacist.

Which magnesium supplements should I take?

There is no simple answer for that, but your health care professional can offer the best guidance. These supplements can interfere with other supplements and medications, and they can adversely affect certain conditions you may have in ways you are unaware of, which is why it is important to speak with a health care professional before taking them.

Viruses are in the air and all around us, from the common cold to COVID-19. Eating a healthy, balanced diet primes and activates your immune system to fight these pathogens, even before you get sick.

In this Q&A, Taylor Stein, Associate Researcher and Registered Dietitian at The Charles Bronfman Institute for Personalized Medicine, Icahn School of Medicine at Mount Sinai, discusses what foods you should eat to support your immune system this cold and flu season.

How does nutrition affect my immune system?

If your diet contains a lot of saturated fatty acids, sugar, and refined carbohydrates, you will not have as strong of an immune response compared to someone consuming diets rich in micronutrients, antioxidants, and fiber. Certain nutrients—specifically vitamins A, D, E, and K—are fat-soluble, meaning they are stored in your fat and take time to accumulate, especially vitamin D. These vitamins support different functions of the immune system and are readily available to fight disease in advance.

Does this mean I need to consume these nutrients before I get sick?

Yes. When you are sick, your immune system is scavenging the body for nutrients, and if you don’t have enough fat-soluble vitamins stored, it can take you longer to get better. Additionally, being sick can affect your ability to eat and drink, so it is very important to have a balanced diet at all times to keep up your stores of these vitamins. Alternatively, vitamins that are water soluble, such as vitamin C and those in the B-complex group, cannot be stored, so you should strive to eat lots of these while you are sick. You also need to eat plenty of macronutrients—carbohydrates, proteins, fiber, and fats.

Taylor Stein, RD

What foods are good for my immune system, and why?

Immune system health largely depends on five food groups:

• Animal meats, fish, dairy products, legumes, nuts, and whole grains. Proteins are the building blocks of cytokines, small proteins that send signals to the immune system telling it where to send white blood cells to fight infections. Since cytokines require different amino acids, you need to eat a variety of protein both from animal and plant-based products. High protein foods contain B-complex vitamins, which are necessary for cell proliferation, which plays an important role in immunity.
• Brightly colored fruits and vegetables. Apricots, kiwi, blueberries, avocados, carrots, strawberries, Swiss chard, bell peppers, raspberries, red onions and other brightly colored produce are filled with both fat-soluble and water-soluble vitamins and are also a great source of fiber.
• Fortified dairy products, eggs, and salmon. These are a great source of vitamin D, which helps activate T cells and has other important functions that affect your immune system. You can also get vitamin D in smaller amounts from nuts and mushrooms. Sunlight is also a great source of vitamin D.
• Nuts, seeds, eggs, legumes, and fish. These all contain disease-fighting minerals, such as zinc, magnesium, and selenium. Pumpkin seeds, almonds, cashews, shellfish, tuna, chickpeas, and lentils are all good sources of these minerals.
• High-fiber, pre-and-probiotic, and fermented foods. These foods are good for your gut, where more than 70 percent of your immune cells live. High-fiber foods include legumes, fruits, and vegetables. Pre-and-probiotic and fermented foods include yogurt, kefir, and buttermilk. These gut-healthy foods are important in maintaining lymphoid tissue in the gastrointestinal tract that helps fight disease.

What are some easy ways to incorporate these foods into my daily diet?

A great way to get more of these foods is to eat them as snacks. For example, snacking on nuts and seeds, bean or guacamole dip, whole grain toast with avocado, and fruit and cheese are all easy ways to get more of the nutrients that prime the immune system. You also need to include them in your main meals. Each dish should include a good source of lean protein—meats, poultry, or fish—and plant-based proteins such as beans, as well as non-starchy vegetables. A simple rule is to fill one quarter of your plate with protein, one quarter with a whole grain or starchy vegetable, and the other half with brightly colored vegetables.

How do these foods compare to taking supplements?

When it comes to immune system health, it is good to have a food-first mentality. Whereas supplements typically provide only one nutrient, a balanced diet filled with whole foods contains all the micro and macronutrients you need. These nutrients work most optimally when they are paired together and are easier to digest than supplements. However, supplements can be a great tool for someone who struggles to eat a variety of foods or has a condition that reduces their ability to consume or prepare healthy food. Keep in mind that supplements are not regulated by the Food and Drug Administration, so it is important to get a doctor or dietitian’s advice on what supplements you should use.

What else is important for my immune system?

Getting plenty of sleep and exercise will also strengthen your immune system. Sleep plays a vital role in hormone production, regulation, and function, which strengthens the immune system, and plays a role in building cytokines. Exercise creates stress in your body and activates the same pathways that are triggered when you’re sick, and gets your body primed and ready for when it needs to fight a pathogen. Lastly, recent studies have found that mental health disorders are associated with decreased immune function, which leads back to sleep hygiene and physical activity. However, mental health can be the cause and effect of not getting enough sleep or exercise. In any case, physical activity, sleep hygiene, and managing mental health are all important to maintaining a healthy immune system.

Most of us want to eat better. But how should you start? Should you ‘kick start’ weight loss with a five-day juice cleanse or maybe try the meat-heavy paleo diet?

It doesn’t need to be that complicated. In fact, juice cleanses and fad diets can sometimes do more harm than good.

Perri Halperin, MS, RD, Clinical Dietitian at The Mount Sinai Hospital, offers some simple ways to develop a healthier diet—without depriving yourself—and explains how working with a nutritionist can help support your weight loss or weight management goals.

What small changes can I make for a healthier diet?

It’s always easier to add something to your diet, rather than subtract. To increase micronutrients and fiber, I recommend adding a non-starchy vegetable—like green beans, carrots, or spinach—or a fruit with every meal.

Make sure to start your day with breakfast. A lot of people think that skipping breakfast is best, but in doing so you are confusing your body. Food is fuel. When you skip breakfast—or any meal—your body holds onto the food it has as an energy reserve. A healthy breakfast, and any meal, includes non-starchy vegetables, fruit, and protein. Protein gives you a feeling of being full, something nutritionists call satiety, after you eat.

Avoid sugar-sweetened beverages. Instead of drinking juice or soda, try fruit-infused water or seltzer. You can infuse water with watermelon, blueberries, strawberries, cucumber, or mint.

Should I count calories?

When you think about calories, focus on quality, not quantity. Eating 300 calories worth of cake, candy, and chips is not the same as eating 300 calories of salad and chicken. Try to have a protein with every meal and snack. Good sources of proteins include eggs; plain nonfat Greek yogurt (which has more protein, less sugar, and a thicker consistency than regular yogurt); low-fat cottage, or ricotta cheese; fish or shellfish; chicken and turkey; beans or chickpeas; seitan or tofu.

If you eat a protein and a non-starchy vegetable at every meal and snack, you will put yourself in the right calorie range. You’ll also feel good because you are giving your body the fuel that it needs. If you do well with counting something, count grams of protein instead of calories. Aim to consume about 60 grams of protein a day. An eight ounce glass of milk skim milk has about 8 grams and a chicken breast has about 30 grams.

Do I need to detox or cleanse my body?  

Your body cannot use food to detox or cleanse. Your body cleanses and detoxes itself using your kidneys and liver. The best way to help your body cleanse itself is to feed it the fuel that it needs to carry out those processes efficiently and without overwhelming those organs.

Are there habits that people think are healthy that are not?

Yes. I call these habits false friends—things we eat or drink because we think they’re healthy but they’re not. Smoothies and juicing are false friends. They trick us into consuming calories and sugar from foods we probably wouldn’t sit down and eat in one sitting. It’s better to eat your food, not drink it.

Granola, granola bars, and trail mix are also false friends. These foods are often high in sugar and fat. A third type of false friend is vitamin and mineral supplements (micronutrients) that our body doesn’t need. Our body’s internal processes help itself maintain equilibrium. When we overload ourselves with B-12 supplements, magnesium, or other supplements that we don’t need, all we’re doing is giving our body an extra job—to get rid of those extraneous micronutrients.

Some people think tropical fruit—like bananas—are off limits, and I want to dispel that myth. Don’t be scared of a banana. It’s true that berries—strawberries, blueberries, blackberries—tend to be lower in sugar than bananas, pineapples, papayas, and mangoes; that doesn’t mean you should never have a banana. It means you should think about variety and moderation when making food choices.

Yogurt choices can be overwhelming. Plain, nonfat Greek yogurt is a good choice. If you need a little flavor, take a look at the label. You should get at least 12 grams of protein and less than six or seven grams of sugar per serving.

How can a nutritionist help me?

Nutritionists can help in a variety of ways, depending on what you need. If you need information, a nutritionist can explain calories, proteins, fats, and carbs. They can help you figure out what to eat. Nutritionists can also help you identify obstacles that may be preventing you from healthy eating. Sometimes you know what to eat, but you’re not eating it. Talking to a nutritionist can help you work through those issues and come up with solutions. In addition, working with a nutritionist can provide accountability.

Like when consulting with any health care professional, it’s important to know what your weight loss and/or weight maintenance goals are and to build a good rapport. Working with a nutritionist can help you live life while reaching these goals. You can celebrate the holidays or go on vacation without sabotaging your efforts or giving up the foods and flavors you love. A nutritionist can help.

Why is it so important to have the right mindset?

In my experience, having the right mindset is the number one indicator of successful weight loss and weight maintenance. People who make the connection between food and exercise choices and how they feel become strong and empowered—and have the most long-term success.

Weight loss, in particular, can feel really overwhelming. You think you need to lose 20 pounds in a month and can’t figure out how to do it. Breaking it down into smaller chunks is helpful. Instead of worrying about 30 dinners at once, look at the meal that’s right in front of you at that moment. Focus on making the best choice you can—then do that again and again. Consistency is important. Don’t let perfection be the enemy of good. Making good choices every day is more effective than one ‘perfect’ meal.

I often hear people say, “I did a liquid diet and it worked, but now I’ve put weight on.” That makes you ask the question: Did it really work? Having the mindset, understanding that getting and maintaining a healthy weight is a lifelong journey with ups and downs, is really important.