Diabetes develops when the body can't make any or enough insulin, and/or when it can't properly use the insulin it makes. For some people with diabetes, the body becomes resistant to insulin. In these cases, insulin is still produced, but the body does not respond to the effects of insulin as it should. This is called insulin resistance. Whether from not enough insulin or the inability to use insulin properly, the result is high levels of glucose in the blood, or hyperglycemia.


In the sunshine, molecules in the skin are converted to vitamin D. But people stay indoors more these days, which could lead to vitamin D deficiency. Research shows that if mice are deprived of vitamin D, they are more likely to become diabetic. In people, observational studies have also found a correlation between D deficiency and type 1. "If you don't have enough D, then [your immune system] doesn't function like it should," says Chantal Mathieu, MD, PhD, a professor of experimental medicine and endocrinology at Katholieke Universiteit Leuven in Belgium. "Vitamin D is not the cause of type 1 diabetes. [But] if you already have a risk, you don't want to have vitamin D deficiency on board because that's going to be one of the little pushes that pushes you in the wrong direction."
Arlan L Rosenbloom, MD is a member of the following medical societies: American Academy of Pediatrics, American College of Epidemiology, American Pediatric Society, Endocrine Society, Pediatric Endocrine Society, Society for Pediatric Research, Florida Chapter of The American Academy of Pediatrics, Florida Pediatric Society, International Society for Pediatric and Adolescent Diabetes

Insulin is a hormone made by your pancreas that acts like a key to let blood sugar into the cells in your body for use as energy. If you have type 2 diabetes, cells don’t respond normally to insulin; this is called insulin resistance. Your pancreas makes more insulin to try to get cells to respond. Eventually your pancreas can’t keep up, and your blood sugar rises, setting the stage for prediabetes and type 2 diabetes. High blood sugar is damaging to the body and can cause other serious health problems, such as heart disease, vision loss, and kidney disease.


Diabetic retinopathy is a leading cause of blindness and visual disability. Diabetes mellitus is associated with damage to the small blood vessels in the retina, resulting in loss of vision. Findings, consistent from study to study, make it possible to suggest that, after 15 years of diabetes, approximately 2% of people become blind, while about 10% develop severe visual handicap. Loss of vision due to certain types of glaucoma and cataract may also be more common in people with diabetes than in those without the disease.
A healthy meal plan for people with diabetes is generally the same as healthy eating for anyone – low in saturated fat, moderate in salt and sugar, with meals based on lean protein, non-starchy vegetables, whole grains, healthy fats, and fruit. Foods that say they are healthier for people with diabetes generally offer no special benefit. Most of them still raise blood glucose levels, are more expensive, and can also have a laxative effect if they contain sugar alcohols.

When you have Type 2 diabetes, you may start out with something called insulin resistance. This means your cells do not respond well to the insulin you are making. "Insulin levels may be quite high, especially in the early stages of the disease. Eventually, your pancreas may not be able to keep up, and insulin secretion goes down," Rettinger explains. Insulin resistance becomes more common as you put on more weight, especially weight around your belly.


When the blood glucose level rises above 160 to 180 mg/dL, glucose spills into the urine. When the level of glucose in the urine rises even higher, the kidneys excrete additional water to dilute the large amount of glucose. Because the kidneys produce excessive urine, people with diabetes urinate large volumes frequently (polyuria). The excessive urination creates abnormal thirst (polydipsia). Because excessive calories are lost in the urine, people may lose weight. To compensate, people often feel excessively hungry.

Heart disease accounts for approximately 50% of all deaths among people with diabetes in industrialized countries. Risk factors for heart disease in people with diabetes include smoking, high blood pressure, high serum cholesterol and obesity. Diabetes negates the protection from heart disease which pre-menopausal women without diabetes experience. Recognition and management of these conditions may delay or prevent heart disease in people with diabetes.
How is it treated? There is no uniform therapy for type 2 diabetes treatment, which depends on the individual person and his or her stage of type 2 diabetes. To learn more about individualization of therapy, please read our patient guide. That said, the ADA and EASD have created treatment recommendation guidelines for type 2 diabetes progression. In all cases, healthy eating, exercise, and weight management are key to effective type 2 diabetes management. As type 2 diabetes progresses, patients may need to add one or more drugs to their treatment regimen.
When there is excess glucose present in the blood, as with type 2 diabetes, the kidneys react by flushing it out of the blood and into the urine. This results in more urine production and the need to urinate more frequently, as well as an increased risk of urinary tract infections (UTIs) in men and women. People with type 2 diabetes are twice as likely to get a UTI as people without the disease, and the risk is higher in women than in men.
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