Cholesterol is a necessary component for living cells. However, high levels of blood cholesterol are associated with an increased risk of heart disease. To complicate matters even more, blood cholesterol can be divided into two types, one of which actually lowers the risk of heart disease! To get the story on cholesterol straight, it's necessary to understand something about how cholesterol works in the body and how it can contribute to heart disease.
Most of the cholesterol in the body is produced by the liver. A significantly smaller amount comes from dietary sources, such as meat, eggs, and dairy products. Cholesterol travels throughout the body via the blood stream, being absorbed by cells along the way to be used for important processes, such as hormone production and cell membrane repair. Because it isn't water soluble, cholesterol is ferried along the bloodstream encased in protein. These cholesterol-filled protein orbs are called lipoproteins. Lipoproteins come in a variety of sizes that behave differently from one another. Broadly, health care providers and scientists talk about low-density lipoproteins (LDL) and high-density lipoproteins (HDL).
The role of both types of cholesterol in heart disease centers around the formation of arterial plaques — fatty, filmy deposits on arterial walls. Over time, plaques become hardened, leading to narrow, rigid arteries that impede blood flow and thereby increase the risk of heart attack. Also, smaller plaques sometimes develop blood clots on their surface, which can then detach and go on to block arteries downstream, potentially leading to heart attack. Although the biochemistry involved isn't simple, the take home message is that LDL contributes to the formation of plaques on the artery walls, while HDL helps prevent their formation. Accordingly, LDL is often called "bad" cholesterol while HDL is called "good" cholesterol. (These terms apply only to blood cholesterol; dietary cholesterol is neither good nor bad in this sense.)
For more information on cholesterol and heart disease, read the Related Q&As listed below.
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!
Beans, seafood, poultry, meat, and eggs. These are just a few sources for protein. Our bodies need protein for numerous functions. Hemoglobin, which carries oxygen, is an essential protein that gives blood its red color when oxygenated. Antibodies, which act as defenders against disease, are composed of proteins. Hormones, some of which are made from amino acids (the building blocks of protein), regulate many systems in our bodies. These include the regulation of metabolism, digestion, and nutrient absorption, and the concentration of blood glucose. Proteins are also used by our cells to regulate the distribution of water and the movement of nutrients in and out of cells, particularly since proteins are one of the components of cell membranes. Furthermore, proteins are involved in blood clotting, acid-base balance, and visual pigmentation.
Considering we need protein to help our bodies carry out and sustain essential physiological functions, a diet very low in protein is obviously not a good idea. The good news is that it is not difficult to obtain sufficient protein from our diet and most Americans have no trouble doing so. Dietary protein can be obtained from animal and vegetable sources. If your diet is insufficient in protein, you could also be deficient in many important vitamins and minerals found in protein-rich foods. Deficiencies could occur in niacin, thiamin, riboflavin, B-12, B-6, iron, zinc, and calcium, among others, depending on what foods are missing from your diet. The effects of prolonged low protein in the diet would eventually manifest themselves as impaired immune function, and irregularities in other bodily functions and systems described above.
The Recommended Dietary Allowances (RDA) for protein are as follows:
Recommended Dietary Allowance for Protein
|Grams of protein needed each day|
|Children ages 1 - 3||13|
|Children ages 4 - 8||19|
|Children ages 9 - 13||34|
|Girls ages 14 - 18||46|
|Boys ages 14 - 18||52|
|Women ages 19 - 70+||46|
|Men ages 19 - 70+||56|
Protein recommendations vary from individual to individual depending on her/his amount of lean body mass.
As you can see, proteins are an integral and necessary part of our functioning. Animal sources, such as meat, fish, poultry, eggs, and dairy products, contain complete proteins — all the amino acids our bodies require to form the proteins we need. Vegetable sources, such as nuts, seeds, legumes (beans, peas, lentils, and soy products), grains (breads and cereals), and green leafy vegetables, contain incomplete proteins. This means that not all of the amino acids are found in one food. Mother Nature is tricky — the amino acids absent in some foods are present in others. Rice and beans, which together have all the essential amino acids, form a complete protein. This is an example of a way vegetarians can make sure they get complete proteins from their diet; however, according to research, it's not necessary to get complete proteins for every meal. Having some amino acids during breakfast and the others during lunch will have the same effect as consuming them together, during the same meal. Your body has the ability to combine complementary proteins as long as their eaten on the same day.
The following is a broad overview of the protein content in different food groups:
|1 cup dairy or soy milk||6-8 g|
|3 oz. lean beef, fish, or poultry||21 g|
|1/2 cup beans||7 g|
|1 slice of bread||3 g|
|1/2 cup cooked vegetables||2 g|
Dietary protein adds up rather quickly, and, as mentioned earlier, without too much effort. In the US, it is rare to find protein deficiencies among the general population. Ours is more a problem of excess than deficiency.
If you have special dietary needs and/or would like some nutrition counseling to help you eat enough protein from your diet, talking with a nutritionist can be a big help. Columbia students on the Morningside campus can use Open Communicator or call 212-854-7426 to make an appointment. Students on the CUMC campus can contact Medical Services at 212-305-3400.
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Dinner's in a few hours. Lunch seems like it was ages ago. You still have to work on a paper, drive your little brother to soccer, and do the dishes. The deliciousness of chocolate and the sweet sugar/caffeine fix it offers may seem to be the only thing to get you through, so you reach for a bar… is that so bad? New research says no, and yes, depending largely on which type of chocolate you choose and how much of it you eat. Cacao, the bean from which chocolate is made, is not itself unhealthy. In fact, it offers many potential health benefits like lowering blood pressure, increasing sensitivity to insulin, improving coronary vasodilatation (widening of blood vessels) as well as other cardiovascular benefits, and acting as an anti-oxidizing agent. But not all chocolates are created equal.
The good guys in chocolate are flavonoids, health-promoting compounds found in plant-based foods (fruits, veggies, nuts, legumes) that belong to a larger class of compounds called polyphenols. In plants, flavonoids work to repair damage and protect from environmental toxins. When we consume plant-based foods rich in flavonoids, it appears that they can act the same ways in our bodies, offering antioxidant protection from free radicals, and protection from plaque formation on our arterial walls.
Dark chocolate is the most flavonoid-rich variety of chocolate, and therefore the most likely to offer health benefits. However, as chocolate is processed flavonoids are lost, and most commercial chocolates are highly processed. Flavonoids also tend to have a bitter flavor, so many commercial chocolates intentionally process them out. In addition, many chocolate products are made with milk, which can interfere with the antioxidant functioning of flavinols, negating most of the potential health benefits. Finally, many chocolate products are laden with caramel, nuts, marshmallow, and other high-fat, high-calorie add-ins that decrease the amount of flavinols in every bite and make a small chocolate snack a hefty caloric load. Even the best, most flavonoid-rich dark chocolate is replete with fat, sugar, and calories (one ounce of any kind of chocolate has about 140 to 150 calories and 9 to 10 grams of fat), so if you're upping the amount of chocolate you eat to gain health benefits, keep in mind that you may want to trim calories in other areas.
One final consideration: there is currently no research that definitively suggests the amount of chocolate that should be eaten to achieve health benefits. You could also get the polyphenol-related health benefits by eating other flavonoid-rich foods like apples, red wine, tea, cranberries, and onions. That said, for most people, enjoying a small piece of dark chocolate once in a while is probably not going to be harmful, and is more favorable than reaching for the common trick-or-treat variety candy bar.
Over time chocolate has gotten a mixed reputation. It used to be seen as a fattening, pimple-producing crutch for the premenstrual. But chocolate does not cause acne, raise blood cholesterol, cause addiction, nor is it fattening if eaten in moderation. More recently, the pendulum has swung in favor of chocolate, which has come to be regarded as a kind of superfood. While it can offer some wonderful benefits, it may not be the antioxidant source of choice for everyone. Chocolate, as well as red wines and certain cheeses, contains phenylethylamine (PEA), a substance that can dilate blood vessels in the brain. People sensitive to PEA might find that eating chocolate can trigger headaches, even migraines. And for those prone to heartburn, chocolate can cause an episode, as would any other high-fat food.
So is chocolate bad for you? Each person should answer this question for themselves taking into consideration which kind of chocolate is within reach and their own health needs. For most healthy and fit individuals, chocolate is a pleasurable and reasonably healthy way to get some flavonoids into the system. For those prone to migraines or who have to watch their fat intake, they might want to stick with the cranberries and onions.
Creatine is a substance manufactured in the human body by the liver and kidneys or obtained from meat in the diet. It is present in muscle, nerve, and sperm cells. In muscles, creatine is used to form phosphocreatine, which can be used to supply energy needed for muscle contractions. It has been suggested that by increasing creatine in the diet, one may increase the amount of phosphocreatine in the muscle, which would then provide a greater availability of high energy phosphate for energy production during muscle contraction. It also may cause the muscles to retain water, a proposed mechanism for the "bulking" effect of the supplement.
No one really knows how much creatine is too much. Some people experience muscle cramps, electrolyte imbalances, fever, or gastrointestinal symptoms like nausea and diarrhea when they take creatine. Long-term effects are much less well-studied. While there is little conclusive evidence for adverse affects, people who have liver or kidney problems or who take diuretics should avoid taking creatine because of the theoretical complications. People with diabetes or who take either medications or supplements that affect blood sugar should also use caution. If you start to notice any side effects, you should stop taking creatine and see your health care provider.
As for benefits, creatine can enhance performance for short bursts of anaerobic activity, like weightlifting. However, people doing aerobic activities, like running or cycling, probably won't see any improvement.
The amount taken in through commercially marketed supplements is far greater than one would be able to ingest via food. Some regimes call for a loading period — perhaps 20 to 25 grams for five days, followed by daily doses of about 5 grams. Non-meat eaters (vegans) may respond better since their natural creatine stores are probably lower than meat-eaters. Since any long-term effects from these high levels are uncertain, your best bet is to let your health care provider know that you take creatine. That way, if you ever do experience side effects, he/she will be better able to help you decide whether to keep pumping up.
Dear Not worried...just curious,
If your diet is leaving you drowsy, it may be related to not eating enough calories — especially since many vegetarian foods tend to be relatively low-calorie. Eating too few calories would leave your body without enough energy to "get up and go" in the morning. To increase your calorie intake, try buying a variety of nuts, seeds (sunflower, pumpkin, etc.), and dried fruits to make your own trail mix: each day, put about one cup into a bag and carry it with you to snack on. Besides added calories, you will also be getting a good source of vitamins, minerals, and some protein into your diet.
At meal times, include healthy size portions of grains (whole wheat, brown rice, oats, barley, buckwheat, etc.), vegetables, fruit, and legumes (dried beans and peas), and use a moderate amount of vegetable oil (canola and olive are good choices) for cooking. If you eat eggs and dairy, they can also serve as a great source of protein, calcium, and added calories.
In terms of exercise, aim for about 30 minutes of aerobic activity five or more times a week to get cardiovascular and energy-boosting benefits. Exercise in excess of about one hour of aerobic activity, five or more times a week, should be reserved for those training for a competitive sport (and who are eating higher-calorie diets!). High levels of exercise increase the risk of sports-related injury and may make it harder to take in a sufficient amount of calories.
Even if you think you sleep the right number of hours, keep in mind that some people, particularly college-aged people, require up to ten hours of sleep a night. Other sleep habits might also give you problems; for example, it's important to try to go to bed and wake up at close to the same time each day. Although this may seem nearly impossible on a student schedule, try to get on an even keel to start off the semester. If you wake up at 11:00 AM most days and get up for an 8:00 AM class two days a week, you most likely will feel like you never quite wake up on the two early days, even if your total amount of sleep is adequate. You may want to adjust your routine so that you go to bed early enough to wake up at the same time each day (weekends included), and see if your tiredness improves.
If you feel overly exhausted or your drowsiness is interfering with school and life activities, you may want to consider seeing your health care provider. Students at Columbia can make an appointment through Open Communicator (Morningside) or by contacting the Student Health Service (CUMC).
Good luck getting up and at 'em!
Dear Cow lover,
Why does a milking stool have only three legs? Because the cow has the udder! Get it? Unfortunately, there’s not such a definitive answer to YOUR question. Research on the health effects of drinking milk has produced mixed results. As with any other food group, it is important to consider the pros and cons of dairy consumption.
Before a discussion of pros and cons, here is a run-down on recent milk research as it relates to osteoporosis. Although it is thought that drinking milk every day helps ward off osteoporosis, a small group of renowned researchers recently found that drinking too much milk can actually contribute to calcium loss. This is because the high amount of protein in milk thins blood and tissue, causing it to become acidic. In order to neutralize the acidity, the body draws out calcium from bones. As a result, the more milk you consume, the more calcium you need to process the protein intake. With that being said, drinking moderate amounts of milk each day (500 to 700 milligrams daily) is still thought to be good for your bones. More information on osteoporosis can be found in Women, calcium, and osteoporosis?
Moooving on, here is a list of the various pros and cons of drinking milk:
- Milk is high in calcium, which is important for healthy bones. Additionally, the calcium in milk is well absorbed by the digestive tract because the vitamin D and lactose found in milk facilitate calcium absorption. Still, it's possible to get ample calcium without drinking dairy milk — by eating foods such as tofu, soy milk, or greens such as kale. See Calcium — how much is enough? for more information.
- Whole milk is brimming with protein, which is beneficial for muscle growth.
- Studies have shown that drinking milk can help regulate weight gain.
- Skim milk is very low in fat and cholesterol, and is a complete source of protein.
- Milk is also a good source of phosphorous, magnesium, vitamin A, vitamin D, and riboflavin (a B vitamin).
- Whole milk is high in saturated fat, which can increase cholesterol level.
- Milk is a common cause of food allergy (allergy to milk protein).
- Many people lack the enzyme to digest lactose (milk sugar). This is called lactose intolerance, which causes bloating, gas, and diarrhea.
- Milk may contain the antibiotics given to the cow while it is lactating. It has been argued that humans subsequently absorb these antibiotics upon drinking milk, potentially leading harmful bacteria to become more resistant to these antibiotics. As a result, when antibiotics are prescribed, they may not be as effective at killing the bacteria.
- Some research has found a correlation between drinking milk that is produced by cows injected with the bovine growth hormone (rBST) and cancer. However, research shows highly mixed results.
As a side note, if you are concerned about the possible effects of antibiotics and rBST on your body, it is possible to buy antibiotic-free (and typically hormone-free, as well) milk from specialty grocers that carry natural foods. Alternatively, you can purchase USDA-certified organic milk, which is available at most supermarkets.
Overall, when researching the pros and cons of milk, it is important to take into account that there are two opposing sides — one that believes that milk is great for the body, and another that believes that milk does not aid against osteoporosis and is even harmful for the body. Whatever camp you choose to join, it is important to be informed. Seize every opportunity (to obtain information), and milk it for all its worth!
Dear Yolking it Up,
Egg powder is usually simply dehydrated eggs, a substitute that people may use when they're camping, or in other situations where there is a lack of refrigeration. Egg powder may also be added to some cake mixes, pancake mixes, and the like, so that the home baker doesn't have to add whole eggs to the mix. A large egg contains about 6 grams of high quality protein, making both eggs and egg powder good sources of protein. Eggs are also an important source of vitamins B12 and E, riboflavin, folacin, iron, and phosphorus. These make it one of nature's near perfect foods, except for the cholesterol — its yolk contains a significant portion of the total daily maximum intake of cholesterol.
Many people experiment with egg whites in order to lower the cholesterol content of their favorite recipes. There are numerous egg substitutes on the market, which come in frozen, refrigerated, and powdered form (this may be what you are referring to in your question). Most of the substitutes have egg whites as their main ingredient. The white of the egg is almost pure protein, containing a near complete balance of complementary amino acids. So, these substitutes are definitely a good source of protein, but not of fat or cholesterol, or B vitamins and minerals.
With the variety of egg substitutes on the market, it's important to read the label carefully. Some have vegetable oil, flavoring, or color added to give the effect of yolk. Other products contain no eggs at all, and are intended to be used in baked products to produce the leavening effect, but would taste terrible as scrambled eggs. The products range in caloric content from 15 to 60 calories per serving, as compared with about 80 calories for a whole egg. Most have little or no cholesterol, but some contain as much as 4 gms of fat per serving.
The American Heart Association recommends limiting average daily cholesterol intake to less than 300 milligrams. If you have heart disease, the recommendation drops to less than 200 milligrams daily. It may make sense to consult with a nutritionist or your health care provider if you already have elevated levels of cholesterol.
As with many foods, moderation is the key to getting "eggs-actly" what is best for your health.
How's this for a treat — you should eat whatever you want to, just as long as it's in moderation. Eating can be for fuel, but can, and many would argue should, be for pleasure as well. Of course, sometimes you have to take the pleasure with some pain; in this case, better make it whole-wheat pain (French for bread). In addition to whole wheat and whole grain products, fresh fruits and vegetables, lean protein and low- or non-fat dairy products should also be eaten regularly in order to ensure that you're getting all the nutrients you need from a healthy and balanced diet.
How much of any food group you should eat depends on your age, sex, weight and activity level. According to the USDA's 2011 MyPlate plan, a typical man aged 19-30 should try to eat eat about 8 ounces of grains, with at least 4 ounces coming from whole grains, 3 cups of vegetables, 2 cups of fruit, 3 cups of dairy products, 6 1/2 ounces of protein (lean meats and beans) and are allowed 7 teaspoons of foods from the oil group.
A typical woman aged 19-30 should try to eat 6 ounces of grains, with 3 ounces coming from whole grains, 2.5 cups of vegetables, 2 cups of fruit, 3 cups of dairy products, 5 1/2 ounces of protein (lean meats and beans) and can consume about 6 teaspoons from the oil group. With a balanced diet like those described above, men and women can eat still eat sweets and treats in moderation and maintain a healthy diet.
These are only guidelines, which can most certainly be tailored to your activity level, medical history, and/or food likes and dislikes. If you are looking for a specific nutritional plan, it's a great idea to discuss any concerns and thoughts with a health care provider. Students at Columbia can make an appointment with a nutritionist or their health care provider by calling x4-2284 or visiting Open Communicator.
If this has whetted your appetite to find out more on what and how much of a food constitutes a serving and what group it comes from, you can check out the choosemyplate.gov site. You can also check out Food Guidelines — How much is a serving? in the Go Ask Alice! archives for more information on serving sizes, as well as where to go to learn more about dietary recommendations. Another great resource is Get Balanced!, Columbia University's Guide for Healthier Eating.
Before discussing their role in maintaining good health, let's first clarify what antioxidants are. "Antioxidant" is the collective name for the vitamins, minerals, carotenoids, and polyphenols that protect the body from harmful free radicals. The most well known antioxidants include the vitamins A (found in liver, dairy, and fish), C (found in bell peppers and citrus fruits), E (found in oils, fortified cereals, seeds, and nuts), and the mineral selenium (found in Brazil nuts, meats, tuna, and plant foods). The carotenoids beta-carotene, lutein, and lycopene also have high antioxidant activity and are responsible for adding color to many fruits and vegetables. Carrots and pumpkins wouldn't be orange without beta-carotene, for example. Lutein, also important in eyesight, is abundant in leafy green vegetables. Lycopene is present in red fruits and vegetables, most notably in tomatoes. No wonder why many experts stress the importance of eating a "colorful" diet!
So why are they called antioxidants? The name is indicative of the mechanism by which they help prevent disease. In humans, a small but significant percentage of oxygen molecules in the body will become electrically charged due to natural cellular activity and/or exposure to environmental factors such as tobacco smoke and radiation. The oxygen molecule becomes a "free radical" as it undergoes this process of oxidation. Free radicals are highly reactive as they try to steal electrons from other molecules, including DNA and cellular membranes. They will continue to react with other cellular molecules in a chain-reaction mechanism. This chain reaction of free radicals can damage cells, which may play a role in the development of certain conditions like heart disease and cancer. Antioxidants, however, stop the chain-reaction by giving up electrons and neutralizing free radicals so that they cannot induce any more oxidative damage. Unlike other molecules, antioxidants do not become reactive when they lose an electron.
Many studies have shown the link between free radicals and a number of degenerative diseases associated with aging. Thus, it is possible that antioxidants can be beneficial in reducing the incidence of cancer, cardiovascular disease, cognitive impairment, Alzheimer's disease, immune dysfunction, cataracts, stroke, and macular degeneration.
Read any fitness magazine, watch a few television ads, or simply pass by your local health food store, and notice the benefits of the latest supplement being touted. While new products emerge frequently, it is best to remember that vitamin and mineral supplements are not to be used as substitutes for a healthy, well-balanced diet. In fact, due to many conflicting studies on the effects of antioxidant supplements, the American Heart Association does not currently recommend using antioxidant vitamin supplements. It is also important to note that we can "over-supplement" our bodies, taking much more than the recommended daily value of certain vitamins and minerals. Vitamins A and E are fat soluble, meaning that excess amounts are stored in the liver and fatty tissues, instead of being quickly excreted, creating a risk of toxicity. Your best bet is to eat a diet rich in fruits, veggies, and whole grains.
For information on cancer, heart disease, and antioxidants (as well as on healthy diets, vitamins and minerals, etc.), you can visit the the National Cancer Institute website. Additional resources on supplements are provided by the National Institute of Health's Office of Dietary Supplements.
Remember, a balanced diet rich in colorful fruits and vegetables can provide you with immediate health and energy benefits and help fight the effects of aging for years to come. Happy antioxidizing!