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Food Sense for All
Good nutrition is important to everyone’s health and can help prevent the onset of such diseases as Diabetes. For those who suffer with Diabetes or pre-diabetes, staying healthy is, in part, a matter of making the right choices when it comes to dietary intake.
Sugars and other carbohydrates are readily converted to glucose, but the rate at which that occurs is measured by something called glycemic index. A high glycemic index indicates a food will rapidly be converted to glucose, causing a rapid spike in blood sugar. A low glycemic index means that the digestive process for that food is slower, meaning a slow production of glucose and a slower rise in blood sugar. For example, white rice rapidly converts to glucose and has a glycemic index of 72, whereas an apple, which converts much more slowly, has a glycemic index of only 36. However, the glycemic load, which includes the effect of typical portion size, may be an even better measure of a particular food’s effect on blood glucose.
Another factor that contributes to the rise in blood sugar is the quantity of food eaten. Eating smaller portions results in lower spikes in blood sugar. For those with pre-diabetes or Type 2 diabetes, simply eating smaller portions more frequently can improve the body’s ability to maintain blood sugars in the proper range. Choosing foods with a lower glycemic index and eating healthy portions, can help keep blood glucose in the normal range.
One area of conflicting research centers on the effects of caffeine on blood glucose. A study published in the June 2016 issue of the European Journal of Nutrition found that the risk of developing Type 2 diabetes was reduced for healthy, regular coffee drinkers consuming three to four cups of coffee per day. However, previous evidence suggests that high doses of caffeine can cause blood glucose to spike. The Mayo Clinic suggests that consuming up to 400 milligrams (mg) of caffeine (about four 8-ounce cups of coffee) is safe for most people, but it can cause trouble (spikes or lows) for those with diabetes. Limiting caffeine intake is a likely a good strategy for improved health.
Considering the health effects of Vitamin D, all divers should strive to maintain healthy levels of this vitamin. Many foods are Vitamin D-enhanced and may have a naturally high dose of Vitamin D. These include salmon, tuna, mackerel and vitamin D-fortified dairy products. Taking Vitamin D supplements is another health-wise strategy that could help maintain pancreatic function and help control blood glucose. The advice of nutritionists is to take Vitamin D3 with a meal that contains fat, since Vitamin D is fat-soluble and this enhances uptake. Foods rich in healthy fat include fish, nuts, avocado and olive oil.
The more we learn about human physiology, health and the effects of the underwater environment, the better prepared we are to make safe adaptations to explore the underwater world. Unfortunately, not everyone can safely enjoy scuba diving, but for many of those with diabetes, the door has been opened with safe diving protocols based on solid scientific research.
Considerations for Candidates
While the criteria for diving with diabetes may vary from one certification agency to another, some of the basic criteria for safe diabetic diving include good control of blood glucose levels and freedom from severe secondary complications of diabetes. As University of the Virgin Islands Dive Safety Officer and Instructor Steve Prosterman points out, “A candidate for diving should have an understanding of the relationship between the disease and exercise, be able to recognize early and handle low blood sugars on their own and not have had a serious hypoglycemic (low blood sugar) episode within the last 12 months.”
One way that diabetics can measure their ability to control the disease is with a hemoglobin A1C test, which provides a 90-day lookback at blood glucose levels and is a good indicator of how well blood glucose is being controlled. Most doctors will recommend that this test be performed at least twice a year. For diving, it may be suggested that the test results be within 30 percent of the normal range. Results that fall outside that range may indicate that better control of blood glucose is needed before a person undertakes underwater activities such as scuba diving.
Also important to safety is the person’s ability to recognize the early warning signs of hypoglycemia. Divers with diabetes must have a clear insight into the relationship between diabetes and exercise and be able to recognize and respond properly when a low blood glucose situation is developing.
Glucose Management: Procedures for Diabetic Divers
Safe diving for diabetic divers requires strict protocols, as well as the development and use of good practices and habits. DAN recommends that divers make a general self-assessment of their fitness for diving on the day of the dive, as well as maintaining good hydration throughout the days of diving. Specific protocols* for glucose management on the day of diving include the following:
Before entering the water, blood glucose (BG) must be stable or rising with a value greater than or equal to 150 mg dL-1 (8.3 mmol L-1). Divers should complete a minimum of three pre-dive BG tests — performed at 60 minutes, 30 minutes and immediately prior to diving — to evaluate BG trends. It is noted that alterations in the dosage of oral hypoglycemic agents (OHA) or insulin on the evening prior or day of diving may help.
Divers should delay the dive if BG is less than 150 mg dL-1 (8.3 mmol L-1) or greater than 300 mg dL-1 (16.7 mmol L-1).
Divers must carry readily accessible oral glucose during all dives and have parenteral glucagon available at the surface.
If hypoglycemia is noticed underwater, the diver should surface (with buddy), establish positive buoyancy, ingest glucose and leave the water.
Check blood sugar frequently for 12-15 hours after diving to ensure safe levels.
In order to establish best practices for future diving, diabetic divers should log all dives and include BG test results and all information pertinent to diabetes management.
For more information, contact DAN and consult your physician.
Also available from DAN: Pollock NW, Uguccioni DM, Dear GdeL, eds. Diabetes and recreational diving: guidelines for the future. Proceedings of the UHMS/DAN 2005 June 19 Workshop. Durham, NC: Divers Alert Network; 2005.
Symptoms of Hypoglycemia
Hypoglycemia is a condition where blood glucose (blood sugar) is low. When levels fall to 60 to 70 mg/dl or less, a dangerous condition exists. Some signs and symptoms of hypoglycemia of which diabetic divers, their buddies and instructors should be aware include:
Weakness or dizziness
Unresponsiveness or inappropriate responsiveness
Sudden mood changes
Loss of consciousness or altered state of consciousness
Diabetic divers who display these symptoms should follow established protocols. This includes exchanging hand signals to identify the problem, ascending and stabilizing at the surface (both the affected diver and the buddy) and ingestion of carbohydrates by the affected diver. The divers terminate the dive and return to the boat or beach where a blood test is performed. Such events, along with blood glucose results and other details of the event, should be recorded for future reference.
Glycemic Index and Load
The glycemic index is a measure of how rapidly a food is converted into glucose through digestion. A high glycemic index means a food converts quickly. The glycemic load is a measure of the impact of a typical portion of the food on blood glucose, taking into account the typical portion size. The values shown in the table below are just a few examples to give you an idea of how foods affect blood glucose and some are quite surprising. As the data suggests, even minor adjustments to diet can have a large impact on blood glucose control. Numerous online sources are available to provide values for a broad spectrum of foods.
By Robert N. Rossier