RDAs (Recommended Dietary Allowances), prepared by the Food and Nutrition Board of the National Academy of Sciences, have been around for over 50 years, with periodic updates. The RDA is the average daily dietary intake level that would adequately meet the nutritional needs of nearly all (98 percent) healthy persons. RDAs include nutrients for which there is sufficient scientific evidence that they are required for good health. Their intention has always been to establish "standards to serve as a goal for good nutrition." RDAs provide the basis for evaluating the adequacy of diets of population groups. They are set at a level that includes a safety factor appropriate to each nutrient; so, this level actually exceeds the requirement for most individuals.
The Food and Nutrition Board has established Dietary Reference Intakes (DRIs). In addition to RDAs, DRIs include recommendations for food components for which RDAs cannot be established. Some of these include fat, carbohydrate, fiber, and plant estrogens, among others. DRIs also include maximum intake levels. Three dietary intake reference values for DRIs are:
- Adequate Intake — the dietary intake level that would adequately sustain health when an RDA cannot be determined because of insufficient scientific evidence.
- Estimated Average Requirement — the estimated dietary intake level that would maintain the health of half of a specified age and sex group.
- Tolerable Upper Intake Level — the maximum level of daily nutrient intake that's apparently safe and unlikely to cause negative health effects in most healthy individuals.
DRIs and RDAs are not developed for specific individuals, but are for the making of policies for feeding programs, food labeling, and food fortification. The numbers signify levels of each compound that are appropriate for most healthy people in each category. To access information on RDAs and DRIs, check out the United States Department of Agriculture's (USDA) Food and Nutrition Information Center website.
Vitamin supplements may contain an amount equivalent to the RDA for DRI, but you'll probably not find a supplement with every imaginable nutrient, vitamin, and mineral. There are innumerable substances that keep us healthy, many of which cannot be packaged in a pill. In addition, many nutrients are difficult for the body to absorb when they come in pill form. Obtaining nutrients directly from a balanced diet of fruits, vegetables, whole grains, and lean proteins is still the recommended manner of giving your body all it needs to be healthy.
To assess whether your current diet is filled with nutrients, check out ChooseMyPlate.gov. You can also speak with your health care provider about whether you need a multivitamin or if the food you eat is sufficient. Students at Columbia can also make an appointment to speak with a registered dietician or a health care provider either through Medical Services (Morningside) or the Student Health Service (CUMC). Take care,
Dear Confused and College Bound,
You are not alone with your concerns. Going to college is a big step in a person's life involving major changes. You and those around you may be living on your own for the first time, making decisions on a buffet of issues, including what to eat.
Eating healthy at college is possible. Many college dining services are offering more healthy choices and are often quite receptive to students' concerns and dietary preferences. But, this is only part of the challenge. In an environment where time, friends, and finances may combine in new ways, having options available only solves some of the puzzle. It's important to experiment with what works best for you. For example, that traditional idea of three square meals a day has been updated with a more contemporary concept of eating five smaller meals spread throughout the day. Steer clear of diets or fads, especially those that drastically limit a particular nutrient. Remember, balance, moderation, and variety win out over trendy and extreme. For some practical tips, navigate through the many options on Choosemyplate.gov. Columbia students can also take advantage of the resources from the Get Balanced initiative. Plan ahead when possible so you don't have to rely on vending machines when you're hungry; think of ways to incorporate fruits, vegetables, and whole grains on a daily basis. Eating more of these will fill you up and possibly even enhance your already stellar brain power.
Making time for physical activity is important, too. Most college fitness centers have a variety of movement classes and options. When the weather is right, grab a friend and walk, run, bike, or blade outdoors. If you are Columbia affiliated, you can connect with the CU Move initiative. CU Move encourages members of the Columbia community to engage in active lives that include regular physical activity. The program provides participants with motivation, incentives to be active throughout the year, and event calendars with access to plenty of free and low-cost physical activity options on campus and around NYC.
Now, to address the second part of your question: an eating disorder, such as anorexia nervosa, is less about food, eating, and body weight. It has more to do with mental health, emotional, physical, socio-cultural, and family issues. If this is a particular concern of yours, you might want to take a look at Eating disorders vs. normal eating. Additionally, if you are a Columbia student, you can make an appointment with a health care provider or a registered dietitian to discuss your concerns by contacting Medical Services (Morningside) or the Student Health Service (CUMC).
Give yourself some time to adjust to a new environment and ask for help when you need it. Everything in moderation, even moderation.
Enjoy your time at college,
As they say, everything in moderation — including fiber! Eating enough fiber can have many health benefits, while too much may have consequences. By learning how much fiber you need, how much is in your food, and adjusting your diet accordingly, you’ll be able to strike a balance that’s ideal for your body (and your bowels).
Fiber is basically composed of plant-based food matter (fruits, veggies, whole grains, and legumes) that can’t be broken down by your digestive system. Whole foods contain both soluble (dissolves in water) and insoluble (does not dissolve in water) fiber. Although the recommendations below don’t distinguish between these two types of fiber, they are different and have distinct functions — soluble fiber helps to reduce cholesterol and glucose levels, and insoluble fiber helps with constipation by increasing fecal bulk.
Overall, fiber may lead to many health benefits, such as:
- Keeping you regular. Fiber decreases the risk of constipation by bulking up and softening your stool.
- Maintaining your bowel health. Fiber may prevent the development of diverticulitis and hemorrhoids. It has also been shown to reduce the symptoms of irritable bowel syndrome (IBS) in some cases.
- Lowering cholesterol and blood glucose levels. By reducing bad (LDL) cholesterol and blood glucose levels, soluble fiber also leads to a decreased risk for cardiovascular disease, coronary heart disease, and type II diabetes.
- Controlling your appetite/weight. Foods that contain fiber are typically low in fat, energy-dense, take more time to chew, keep you full for longer, and block some of the digestion of fats and proteins.
- Preventing cancer. Fiber consumption may lower the risk for colorectal cancer, but the evidence is not yet conclusive.
Curious if you are getting enough fiber in your diet? You can use either the USDA Food List or WebMD’s Fiber-o-Meter to figure out the fiber content of the foods you eat and get suggestions for high-fiber foods. Making a habit out of reading the nutrition facts on food labels will also help. Generally, women need less fiber than men, and those aged 51 years or older need less than younger individuals. The following table can give you an idea of how much fiber you need on a daily basis:
Age 50 or younger
Age 51 or older
Source: Institute of Medicine
However, having too much fiber in one's diet can cause problems. When the intake of fiber is too high, it can replace other energy and nutrients that you need in your diet. Some insoluble fibers bind certain minerals, including calcium, magnesium, phosphorous, and iron. Too much fiber can also cause abdominal discomfort, gas, and diarrhea, and block the gastrointestinal (GI) tract if you add too much fiber too fast. For some, fiber supplements may potentially cause additional, more severe side effects such as allergic reactions and asthma, gastrointestinal distress, and drug and nutrient interactions. If you feel that you might benefit from taking fiber supplements, it's best to speak with a health care provider first to make sure it’s right for you.
So, before you load up on fiber, try adding it to your diet gradually, so that your GI tract has time to adapt. You'll also want to drink lots of fluids to keep the fiber soft. Choosing a variety of soluble and insoluble fiber-rich food sources, such as fruits, vegetables, whole grain breads and cereals, and legumes (beans and peas) will ensure that not only will you get a good mix of fiber, but beneficial nutrients, too. Remember that brown rice and 100 percent whole wheat bread have more fiber than white rice or white bread. Also, eating the skins of your fruits and vegetables whenever possible can also help increase fiber intake. If you're a Columbia student and need advice or more information about incorporating fiber-rich foods into a balanced diet, you can make an appointment with a health care provider or a registered dietitian by contacting Medical Services (Morningside) or the Student Health Service (CUMC).
Hope this was helpful!
Dear Supplementally Confused,
It may depend on the type of dietary supplement. Supplements range from daily multi-vitamins and minerals to anabolic steroids. Certain supplements are recommended for various conditions. For example, calcium supplements are often encouraged to help prevent osteoporosis, and iron is recommended for those who are anemic. Pregnant women's increased nutritional needs may require that they supplement with vitamins and minerals. The performance enhancing supplements that are so widely advertised today (i.e., creatine, chromium picolinate, protein shakes, amino acids) are not needed by the average person.
The best way to get all of the nutrients your body needs is to eat a healthy diet. To do this, you should eat a variety of foods, have a good balance within the food groups (read Food Guidelines — How much is a serving? for details), eat enough calories (at least 1200), and make nutrient-dense choices, such as whole wheat bread and skim milk as opposed to white bread and whole milk.
Although vitamin and mineral supplements serve an important purpose for some people, you cannot depend on pills alone to provide your body with the nutrients it needs. Pills do not have phytochemicals, the non-nutrient compounds found in plant-derived foods that have biological activity in the body. Approximately 150 phytochemicals are found in foods along with the vitamins and minerals the body needs. Phytochemicals play a very important role in helping the body defend itself against cancer and cancer-causing agents, and probably many other things as well. An example of a known phytochemical is beta-carotene, a carotenoid. It is found in deeply pigmented fruits and vegetables, such as carrots, sweet potatoes, tomatoes, spinach, broccoli, cantaloupe, pumpkin, and apricots. Carotenoids act as antioxidants, reducing the risk of cancer. Read Antioxidants for more info.
So the best bet is to do what you were told as a child and, "eat your fruits and veggies!" Five servings a day is a great start. If you do supplement, be careful not to overdose. More of a "good" thing is not necessarily good for you. Besides being expensive, over-supplementing can be harmful to you. For more information, read What's the difference between vitamins and minerals? from the Go Ask Alice! Nutrition & Physical Activity archives.
How much did you bet? It's time for your co-worker to pay up!
The human body can survive a surprisingly long time on water alone, but it is nowhere near six months. When the body is deprived of new fuel (i.e., food), it breaks into its energy reserves to keep going. The body stores energy in the form of carbohydrates, fats, and proteins.
After one day without food, the body will have used up its carbohydrates, which are stored as glycogen in liver and muscle cells. After that, it's on to the fat reserves. Your average Joe/Jane, weight-wise, has enough fat reserves to live for four to six weeks without food. After that, the body begins to use its protein reserves (basically, the body itself). Body proteins are used up at a much faster rate than fat, and you could really only get another two to three weeks out of protein. At that point, however, you can't really call it living since so much irreparable damage has been done to the body, including the brain.
Bottom line: an average person could live for about eight weeks on water alone, give or take about a week for an over- or underweight person, respectively.
Eating fruits and vegetables is an essential part of maintaining good health. In 2011, the USDA launched its most recent food guide called Choose My Plate. Most health professionals and health promotion organizations, including the USDA, recommend eating at least five servings of fruits and vegetables daily. Or, in the case of the Choose My Plate campaign, make half of your plate fruits and vegetables.
Since eating vegetables is not very appealing to you, let's start by discussing ways to incorporate some essential vitamins and minerals into your diet via fruit. Look to a wide variety of fruits to take in more vitamins, minerals, and phytochemicals, which are plant substances that may ward off heart disease and certain forms of cancer. For example, a fruit salad composed of oranges, assorted berries, grapes, kiwi, bananas, apples, and peaches with fresh lime juice squeezed over it can be enjoyed as a delicious part of any meal or on its own as a snack. A piece of fruit, such as an apple or a pear, is also an excellent dessert and can be paired with protein, such as nut butter or cheese, to make a well balanced snack.
Now let's move to the incorporation of vegetables in a positive way. Vegetables can taste bitter, particularly when eaten raw. A good place to begin may be experimenting with roasting a few different vegetables to see what you may like. Roasting vegetables brings out their sweetness via a process called caramelization, which reveals the sugars in vegetables, causing them to taste sweeter. This works particularly well with root vegetables, such as onions, potatoes, sweet potatoes, turnips, and carrots. To roast vegetables, simply cut them into one-inch squares, toss with olive oil, salt, and pepper, place on a baking sheet, and put in an oven at 450 degrees for 30 to 40 minutes, tossing and turning throughout cooking. You will know they are done when they are golden brown, slightly crispy on the outside, and soft on the inside. Broccoli and cauliflower are also delicious when roasted. Feel free to experiment by adding grated parmesan or other cheeses, herbs, and spices to the vegetables after roasting. You can also look to "sweeter" vegetables, such as corn, peas, tomatoes, and carrots and incorporate them into pasta or rice dishes or put them together to make a salad. The Get Balanced! nutrition initiative offers some recipes to get you started, such as the Cilantro Corn Tomato Salad.
It is also possible to disguise vegetables in your food, similar to the way some parents do when their children don't eat their veggies. This is typically done using vegetable purees, which can be made at home simply by microwaving a vegetable and then pureeing it, or can be found in the freezer section (most often found are pureed sweet potatoes or squash) or as jars of baby food in the children's section of your grocery store. Purees can be added to stew, soup, pasta sauce, baked goods, etc.; the options are endless. There are several good cookbooks available that offer recipes that incorporate vegetable purees. You can also sneak in an extra veggie by making fruit smoothies with spinach added in — all you'll taste is the fruit!
In addition to purees, you can also incorporate vegetables into other foods. Examples include:
- Make omelets with tomatoes, peppers, and/or mushrooms — be sure to sauté the vegetables first before adding the eggs.
- Add broccoli and/or olives to your pizza.
- Add chopped spinach and/or grated carrots and onions to turkey burgers or meatloaf.
- Mix chopped carrot and celery into tuna or chicken salad.
- Choose soups rich in vegetables, such as Minestrone or Gumbo.
- Add peas, carrots, and/or zucchini to rice pilaf.
It's difficult to "force" yourself into liking a specific food, especially if you are turned off by the taste. Luckily, you can choose from a variety of vegetable options and cooking methods. Keep an open mind (and mouth), and perhaps you will come to enjoy some of these foods!
For more tips about healthy eating, fruits, and vegetables, check out the Optimal Nutrition section of the Go Ask Alice! archive, learn more about the tools from Columbia's Get Balanced initiative, or visit Choosemyplate.gov.
Dear What D'Ya Thinko About Ginkgo,
Gingko (Latin name, Ginkgo biloba) has been part of Chinese traditional medicine for thousands of years. It is extracted from the leaves of the hardy ginkgo biloba tree and is available in a variety of forms, including teas and tablets. Proponents of ginkgo believe that consuming the leaves increases cerebral blood flow and prevents the lumping of platelets in brain tissue. They also believe that ginkgo has other health benefits, such as slowing memory loss, improving cognitive ability, and curing conditions such as asthma, PMS, multiple sclerosis, and sexual dysfunction. For one herb, that's quite a resume!
While some claims on the Ginkgo plant may have some merit, not all are backed by research. Some studies have found that ginkgo biloba has positive effects on cognitive ability, though others have found that this may not be true. Ginkgo has been found to have possible antioxidant properties, which means that it may help the body fight free radicals. Free radicals in the brain attack healthy cells, stealing the cells' electrons. As an antioxidant, ingested ginkgo provides a target for these hungry cells, allowing them to steal ginkgo's electrons rather than from the healthy cells. Ginkgo has been found to be helpful in some patients with claudication (painful legs due to clogged arteries) and dementia. Despite these findings, more research is needed to establish ginkgo as the panacea that it's believed to be.
So, let's say you decide to ginkgo. You may be wondering about the recommended dose. For adults 18 and older, common dosage is typically around 80 to 240 mg, and may be taken two to three times a day (depending on the reason for use). It’s recommended that if you’re just starting to take ginkgo, it’s best to not take any more than 120 mg per day to avoid some gastrointestinal upset. Ginkgo might be safe for children, but it's probably a good idea not to give it to them unless it's under the strict supervision of a health care provider.
Ginkgo, though it is natural, may cause side effects, such as bleeding, headache, nausea, dizziness, diarrhea, and allergic reactions (some of which may be severe). Moreover, the U.S. Food and Drug Administration does not regulate ginkgo or other supplements. As such, it's recommended you ask your health care provider, if you are considering taking ginkgo, especially if you have a bleeding disorder or if you are taking any other medications/supplements. For more information about ginkgo, you may want to check out the section on supplements and ergonenic aids in the Go Ask Alice! Nutrition & Physical Activity archives.
Doing your homework on complementary and alternative medicine is a wise step to take — be proud of yourself for learning more info before you gink-go or gink-no.
The benefits and side effects of melatonin are still under review by researchers and medical professionals — so any discussion about those should be considered tentative, based on what is known thus far. Similar to a wide array of supplements available over the counter, manufacturers do not need Food and Drug Administration (FDA) approval before marketing dietary supplements like melatonin. So, exercising caution and asking questions of a trusted health expert can really help consumers make more informed choices.
Melatonin is a hormone produced by the pineal gland in the brain that has a quick acting, sleep-inducing effect (more like Mellow-tonin, am I right?). It is a light-sensitive hormone, meaning that the absence of light stimulates its secretion. Melatonin may play a role in controlling the circadian rhythm, the body's internal clock and sleep cycle. Before puberty, the pineal gland produces comparatively large amounts of melatonin. As we age, melatonin production continually decreases, perhaps explaining why older people either have difficulty sleeping, or sleep less.
The melatonin you may find in health food stores and pharmacies is actually a synthetic version of the hormone; you can also purchase a form that combines synthetic and natural (from sheep pineal glands) melatonin. Both types of melatonin mimic the real thing in chemical composition and behavior. However, some people favor the entirely synthetic form because it does not carry the risk of contamination that the partially organic form does. Research has also found melatonin in some food sources, including meats, eggs, many vegetables, fruits, seeds, oils, coffee, tea, wine, and beer. Consumption of melatonin from food sources may increase the circulation of melatonin and it’s benefits as an antioxidant, but more research is needed on these potential benefits.
Many claims have been made to melatonin's miraculous powers. So far, scientific evidence has revealed melatonin to be clearly beneficial for a few sleep issues — like insomnia, jet lag, and delayed sleep syndrome. However, recent studies also reveal potential benefits in the following areas:
- reducing pre-operative anxiety and post-operative pain
- improving symptoms of irritable bowel syndrome (IBS)
- reducing symptoms of depression and anxiety in patients undergoing breast cancer surgery
Melatonin taken in recommended doses between one and three months in duration may have very few negative side effects. That said, side effects are possible. Special caution is advised if you:
- are pregnant, breast-feeding, or trying to get pregnant
- are younger than 18 years old
- have high blood pressure
- have diabetes
- have depression
- have a seizure disorder
Depending on what your intended use is for melatonin, dosing can vary. And just like many medications, people can respond very differently to melatonin — some people are more sensitive than others to the supplement and dosage may factor into this as well. If you decide to supplement with melatonin, it's best to discuss dosage recommendations with a health care provider. Too high a dose could lead to anxiety. Large doses of melatonin to children under 15 could also cause seizures.
More research is still needed in all of these arenas — evidence regarding the long-term use of melatonin, in addition to its benefits and side-effects, may not be available for years to come. Talking with a health care provider about taking melatonin can help you decide if you're at high risk for negative side effects.
Hope this helps!
Dear Future Veggie,
Yes, absolutely! Columbia Health has lots of resources for you as you prepare to make the switch. When planning out a healthy vegetarian diet, it is certainly helpful to have some guidance. Get Balanced! Columbia University's Guide for Healthier Eating provides a ton of great information on making healthy food choices as a vegetarian or vegan. Columbia students can also meet with a registered dietitian through Columbia Health. Before meeting with a professional, it may be helpful to do some background research. Check out the related questions below for a plethora of useful information!
It's a great idea to plan consciously when switching over to a vegetarian diet. Not eating meat can offer many health benefits, as well as addressing environmental and ethical concerns. However, people who make the change without learning about proper nutrition can very easily become deficient in certain nutrients, experience undesired weight gain or loss, and fall into the famous trap of becoming a "pasta" vegetarian who lives on carbs and sweets and not much else.
Have you thought about to what degree of vegetarianism you will pledge? There are many variations on the vegetarian diet, including: lacto-ovo, vegetarians who avoid all meat but eat milk and eggs; pescatarians, who eat fish, and do not eat other types of meat; vegans, who avoid all animal products including milk, eggs, and even honey (produced by bees); raw foodists, who eat only raw fruits, veggies, sprouted nuts and grains; and even fruititarians, who only eat fruits, nuts, and seeds. Wherever you fall on the vegetarian spectrum, here are some general tips on converting to a vegetarian diet:
- Plan to incorporate into your diet a wide variety of whole grains, fruits, vegetables, legumes, nuts, seeds, vegetable oils, and of course leave room for some decadent delights (think: vegan triple chocolate cake).
- Ensure that you are eating adequate amounts of non-meat proteins, necessary for long-term sustained energy, and to repair and replace worn-out body cells. High protein veggie foods include beans, nuts (including peanuts and almonds), and milk.
- Vitamins B-12 and D, calcium, iron, and zinc are other nutrients important to pay attention to, as they are abundantly found in meat, but not as easy to find in plant foods. Some strategizing with a nutritionist or educating yourself about vegetarian sources for these nutrients will help you make sure you're getting enough of these important nutrients.
- Because vegetarian diets are often high in fiber, remember to drink lots of water to ensure all that roughage is moving through and out of your system efficiently. Six to eight glasses per day is the general recommendation.
When planning a vegetarian diet, it is important to take into consideration a number of variables, such as body size, activity level, health status, and food preferences. But standing behind your ethical beliefs with the food you take in and the industries you support is an admirable and worthwhile undertaking. With the right guidance, education, and support, you could enjoy great health, a happy and clean conscience, and the joy of being an inspiration and teacher for others who wish to join you!
While jetting cross-country can be a fun adventure, coping with jet lag is often an unwelcome effect. Jet lag is a temporary disorder that occurs when air travelers rapidly travel across three or more time zones. Traversing time zones appears to interfere with a person's production of melatonin, a hormone that helps regulate our sleep-wake cycles (see Melatonin from the Go Ask Alice! archives for more information). This may explain why jet travel disrupts our sleeping patterns and why it takes a while for us to adjust to a new time zone. Travelers have the option of taking melatonin to help counteract the effects that flying has on getting a good night's sleep.
Taking melatonin to reduce jet lag is a well-tested and safe use of the hormone. When the goal is to be in bed and asleep during the normal nighttime hours of your destination, timing is everything. If you take melatonin at the wrong time while still at home in New York, you may land safely in London, but your inner clock may be wandering around the Los Angeles airport wondering how it got on the wrong flight! So, what's the trick?
The secret to shifting your internal clock lies in the direction of your flight and duration of your journey. Travelers who cross three or more time zones generally require more time to adjust. Depending on your travel direction, it is recommended to take melatonin as follows:
- Westward travel is associated with early evening sleepiness and predawn awakening. When traveling westward, melatonin can be taken in the morning.
- Traveling to the east is associated with struggling to fall asleep at the destination bedtime and difficulty arising in the morning. In this case, it is best to take melatonin in the evening at your local time.
- Melatonin can be taken 30 minutes before sleeping. You can also ask your health care provider about the right time to take it.
- Though side effects are uncommon, it is a good idea to avoid alcohol when using melatonin.
The severity of jet lag is also dependent on whether a person is able to sleep while traveling, their age, and the availability of local circadian time cues at the destination (such as natural sunlight). Other than taking melatonin, your health care provider may recommend that you:
- Avoid alcohol, large meals, and caffeinated beverages during travel
- Eat meals at the appropriate time of your destination
- Drink plenty of water
- Sleep, if possible, during long flights
- Consider timed bright light exposure prior to and during travel
- Take sleep-inducing medications, such as zolpidem (Ambien), eszopiclone (Lunesta) and zaleplon (Sonata), during travel and to help you sleep during the first couple of days after your arrival
While adjusting to a new time zone may seem like a drag, don't worry, for your body will adjust in due time. Jet lag may last for several days, but it is a temporary condition that is normally manageable. Whether or not you choose to take melatonin depends on the severity of your jet lag and your preference to induce sleep. In the meantime, don't forget to adjust your watch as well. Happy (and restful) travels!