I heard watermelon has a high glycemic index. Does that mean I should avoid it?

WatermelonThis is an excellent example of how a little information can be misconstrued. I can understand why people are confused, since this is a complicated topic. But, you can rest assured that real foods, such as watermelon, remain good for us despite the glycemic index.

The glycemic index (GI) ranks foods on a scale of 1 to 100 by how quickly they convert to glucose and raise blood sugar levels. For example, pure glucose scores a 100, while peanuts score about 14. The lower the number, the gentler the rise in blood sugar, and the more likely a food will help with weight loss and lower your risk for a host of other ills, including heart disease and diabetes. A diet loaded with high glycemic foods does just the opposite. Many factors influence how fast the body digests a carb-rich food, but in general, the less processed a food, the lower its GI score and the more likely it will improve a person’s health risk and help someone lose weight. The GI is  complicated, since a food’s score will change based on other foods at the meal. GI scores also vary from person to person and even fluctuate enormously in the same person from day to day.

Granted, watermelon has a high GI score of 72, but this natural, unprocessed fruit remains a healthful food because of another factor called the “glycemic load.” This factor compares a food’s GI score with the amount of calories and carbs in the food,. The glycemic load is a much better indicator of a food’s ability to prevent or contribute to disease, since a food that has a large amount of carbs AND dramatically raises blood sugar levels obviously increases the chances of weight gain more than a food that might temporarily raise blood sugar levels, but has few calories. A low GL is associated with a lower risk for insulin resistance, metabolic syndrome, and weight gain.

Let’s put this information into real terms. A potato or a corn tortilla have high glycemic scores and pack a hefty dose of carbs, while watermelon has a high GI score, but few calories or carbs. The former will increase the chances of those extra calories being funneled into fat cells, but watermelon just fills you up, without filling you out. The same can be said for other healthful foods, such as carrots. In general, a glycemic load of 10 or less is low, 11 to 19 is medium, and 20 or greater is considered high. For comparison sake, a carrot has a GL of 3.5, watermelon has a GL of 3.6,  potatoes have a GL of 18, and  a corn tortilla has a GL of 25.

All of this is interesting, but in reality, who wants to memorize a bunch of GI or GL scores?! That’s even worse than counting fat grams and calories. In fact, nations have considered placing GI or GL information on packaged foods and decided against it, siting concerns that those claims would be misleading. Rather than obsess about the numbers, the simple guideline for eating in tune with blood sugar and waistline is to choose lots of wholesome, natural foods, such as watermelon and other fruits and vegetables, whole grains, nuts, legumes, and seafood, which automatically lower the overall GI score and keep a person healthy throughout life.

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My mother takes quite a few medications. Can drugs affect her nutrition?

 How do you quantify pain? Yes! In fact, long term, and in some cases even short-term, use of certain medications might pose serious concerns for a person’s nutritional status.

Prescription and non-prescription medications can affect a person’s nutritional status by several mechanisms. Drugs can increase and decrease appetite, alter the absorption of nutrients in the intestine, affect how nutrients are used within the body, and increase the excretion of nutrients. Medications also can alter the amount and site of nutrient storage within the body. For example, oral contraceptives affect the distribution of vitamin B12 in the tissues.

Take vitamin B6 for an example. This vitamin functions as a co-enzyme in several metabolic reactions that involve the breakdown, build-up, and alteration of proteins and their components, the amino acids. Any drug that contains one or more amino acids might potentially bind to vitamin B6 and inhibit its function. Several categories of drugs interfere with vitamin B6. A drug-induced vitamin B6 deficiency does not produce obvious symptoms; however, physiological and psychological changes can develop when this nutrient is at marginal levels, including an increased risk for cardiovascular disease, irregular sleep habits, anemia, irritability, lethargy, and a reduced ability to handle stress.

Prescription and non-prescription medications often aggravate a pre-existing nutrient deficiency. Chronic poor dietary intake or malabsorption of dietary nutrients can produce deficiencies that often go unnoticed, especially in seniors. A medication that interferes with nutrient status only aggravates subtle deficiencies. For example, many medications commonly used by women of childbearing age, including aspirin and oral contraceptives, alter folic acid metabolism and could aggravate an already compromised folate status. Other minerals marginally supplied in women’s diets, such as calcium, iron, magnesium, and zinc, are further depleted by taking common prescription drugs, such as tetracycline, neomycin, alcohol, aspirin, and primadone.

The extent that a drug influences a person’s nutritional state depends on: 1) the body’s nutrient reserves prior to and during medication therapy; 2) age, size, and medical condition; 3) individual variations in absorption and excretion of nutrients; 4) the adequacy of dietary intake; and 5) the amount and duration of drug therapy.

More attention by the medical community must be given to these potentially serious interactions, especially in seniors who may be taking one or more medications for long periods of time, who typically consume suboptimal diets, and who are prone to reduced absorption of and increased requirements for nutrients.  Photo credit: Chuck Olsen via Compfight

I’ve been hearing a lot about a supplement called DHEA. What is it?

PillsCreative Commons License DHEA is a steroid hormone produced in the adrenal glands and a building block for the sex hormones – estrogen and testosterone. Levels of  the hormone drop at a rate of about 3% a year; by the time people reach 70-years of age, they have only about 10% to 20% of the DHEA they had in their 20s. People take DHEA supplements in the hopes of improving mood and sleep patterns, increasing energy and libido, counteracting stress, preserving muscle, strengthening the immune system, and helping prevent heart disease and cancer. (Dosage? No one knows. Most studies used about 50mg daily.)

But, there are risks, including an increased risk for acne, prostate cancer, aggressiveness, and liver damage. Long-term consequences are unknown. In addition, the purity and strength of supplements are not regulated. Supplements made from wild Mexican yams claim to contain the building blocks for DHEA, but there is little or no evidence that the body converts these compounds into DHEA. Unless people are advised by their physicians to take DHEA, supplementing with this hormone is a buyer-beware decision. I recommend a natural alternative, which is: A few studies show that people who meditate have higher DHEA levels than nonmeditators. Photo credit:  Keith Ramsey via Compfight

Is the old wives’ tale about fish being brain food really true?

Miniature Salmon Prep Board Yes! Your brain is very greasy, but in a good way. More than 60% of it is fat. Unlike the lazy fat stored on the hips or belly, fat in the brain is a worker bee. It makes up the cell membranes that surround each cell and the insulation sheath around neurons that allows thoughts to travel fast from one cell to another. The more fluid and flexible those membranes, the faster you react, the more you remember, and the more creative and clever you are. The most fluid fats are the omega-3s, and the brain must love the omega-3 DHA, because 97% of the omega-3s in your brain are DHA. An accumulating body of research is showing that children, adolescents, and young adults think better, perform better on tests, and react faster when their diets are optimal in DHA. A recent study found that children performed up to 50% better on reading tests when they supplemented with the omega-3s, and studies (including the MIDAS study) find that seniors remember more and might even be at lower risk for dementia and Alzheimer’s when daily intake averages between 220 and 900 milligrams. Note: your body can’t make this fat. It has to come from the diet. That means at least 2 to 3 servings a week of fatty fish, such as salmon, mackerel, or herring. Or, take a fish oil or DHA supplement that lists specifically how much DHA is in each capsule. Photo credit: Stéphanie Kilgast via Compfight

I’ve lost about 30 pounds. Do I have to exercise to keep it off, or can I just continue my diet?

* No diet on the planet will maintain a healthy weight if you don’t exercise. The trick is how much? Most health experts recommend that Americans exercise at least a half hour most days of the week, but people who have lost weight – and more importantly maintained the weight loss – are moving much more than that. They get lots of exercise; the equivalent of an hour or more a day or 28 miles of walking a week, which means they probably have much less time to veg out in front of the TV.  The more weight you have lost and need to maintain, the more you have to move. Researchers don’t understand why a formally obese person must exercise more than an always-lean person to maintain the lower weight, although they speculate it probably relates to some kind of permanent metabolic slowdown that results from having been obese. It’s not fair that you need to move 12,000 steps a day, while your skinny neighbor might need only 8,000 steps, but that’s the reality. To spice up their active lives, weight-loss maintainers turn to variety, with six out of every ten masters incorporating two or more types of exercise into their weekly routines.  Photo credit: Chris JL via Compfight