Mary M. Fynn, Ph.D, RD, L.D.N

Food as Medicine

What is diabetes?


Glucose, a type of sugar found in your blood, is an important source of energy for the body.  Your body can store some glucose to use for energy when you need it.  Diabetes means that your blood glucose (or blood “sugar”) is not being completely stored.   The hormone that stores glucose in the blood is insulin.  We make insulin in the pancreas.  Insulin is released into the bloodstream when the amount of glucose in the blood is increasing, like after a meal.  The insulin then works to remove the glucose from your blood and get it into the cells where it is used for energy or stored.


Diabetes means that your blood sugar (glucose) is not being completely stored.  Type 2 diabetes is the most common form of diabetes. Type 2 diabetes means that the insulin being made is not working as well as it should so not all of the blood glucose is stored.  Someone with type 2 diabetes has too much glucose in their blood.


“Fasting blood glucose” (FBG) is the amount of glucose in the blood when a person has not had any foods or drinks with calories for at least 8 hours.  A healthy level of fasting blood glucose is less than 100 mg/dl.


The healthiest diet to treat type 2 diabetes is a diet moderate in healthy fats and moderate in carbohydrate.  When foods that contain carbohydrate are digested and absorbed, they enter the body as glucose.  So food that contains mostly carbohydrate is the most important food for a diabetic to know what they are eating.


Food groups that contain carbohydrate:

Food Serving size Carbohydrate in a serving
Vegetables ½ cup


Fruits ½ cup = ½ piece of fruit

1 cup of berries or melons



Starch 1 oz. pasta, uncooked

½ cup rice or raw potatoes

1 slice of bread


1 cup milk or plain yogurt



There is also carbohydrate in white and brown sugar and other sweeteners so any food that contains sweeteners also has carbohydrate.  You would need to read the ingredient label to find out if a food contained sugar.  Some words for sugar are: fructose, high fructose corn syrup.


The amount of carbohydrate you can eat each day is based on your total calories and is typically about half of your total calories per day

What are blood fats and how are they related to heart disease?

Blood fats are cholesterol and triglycerides.  These are 2 values that are reported on your lab results.  High levels of cholesterol and triglycerides have both been related to an increase risk of heart disease.  The participles that carry your blood fats are called “lipoproteins”.  The 2 lipoproteins that would be on your lab results are HDL and LDL.


HDL stands for “high density lipoprotein”.  HDL is thought to protect you from heart disease, so you want you HDL to be as high as possible.


Healthy levels of HDL:       men    40 mg/dl or higher; women 50 mg/dl or higher


Diet and HDL: diets low in fat will decrease your HDL.  Diets moderate in fat, especially healthy fats like extra virgin olive oil, will lead to higher and healthier levels of HDL than low fat diets.  Some studies have shown that extra virgin olive oil will increase the level of HDL more than other diet fats.


LDL stands for “low density lipoprotein”.  LDL is the main carrier of cholesterol in the blood and higher levels of LDL are thought to increase your risk of heart disease.  A healthy level of LDL can vary and will depend on if you already have heart disease or diabetes, but many people think a healthy level of LDL is no more than 130 mg/dl.


Diet and LDL:  solid or saturated fats can increase LDL.  These are found in red meat and other animal fats.  Red meat has been related to increasing your risk of heart disease (and some cancers); a healthy diet is low in red meat.  Even though some studies show that dairy fat can raise LDL, dairy fat is not related to increasing heart disease.  So eating less red meat would help to decrease your risk of heart disease, but full fat dairy does not increase your risk.  LDL levels do not change that much with diet.  However, using extra virgin olive oil will contribute to a healthy LDL particle or one less likely to contribute to heart disease; vegetable oils (including margarine and salad dressing) will lead to oxidized LDL, which contribute to heart disease.


Triglycerides are blood fat.  Triglycerides can be stored as fat in our bodies and it can be used as energy by cells.   Triglycerides need to be measured after you have fasted for 10 to 12 hours.  Lab results will list triglycerides as normal if the value is less than 150 mg/dl; however, a healthy level of fasting triglyceride is less than 100 mg/dl.


Diet and triglyceride:  diets too low in fat will raise your blood triglycerides (and lower your HDL).  A diet moderate in fat will lower your triglycerides.  A moderate amount of fat would be about 60 to 70 grams for 1500 calories and 70 to 80 grams for 1800 calories.  Extra virgin olive oil olive oil is a healthy source of oil.  Vegetable oils can contribute to oxidation of LDL, which will increase heart disease risk.

High blood pressure increases your risk of heart disease and stroke.  Your blood pressure can increase if you are overweight, and any weight loss (even small amounts) will lower your blood pressure.  There are 2 minerals that can change your blood pressure: sodium and potassium.


Sodium.  Eating high amounts of sodium can increase your blood pressure.  Some sodium is found naturally in food but the main diet source of sodium is that added to food in processing; this includes foods that are in packages, cans, prepared meals and foods from Fast Food restaurants.  Eating less of these foods will lower the amount of sodium in your diet.  Most people with high blood pressure can add salt to the water to cook pasta, rice or potatoes.  You can even add small amounts of salt to foods.  You should eat less food that is in a package (crackers, cereals, cookies, snack foods, etc), canned (vegetables, pasta meals, etc), prepared meals and less foods from Fast Food restaurants to lower your sodium intake.


Potassium.  All vegetables and fruits contain potassium.  Eating a diet high in potassium, or eating more fruits and vegetables, will help to decrease your blood pressure.  A serving of both vegetables and fruits is ½ cup; a serving of leafy greens, such as lettuce or spinach,  is 1 cups; most pieces of fruit are 2 servings.   The DASH study (Dietary Approaches to Stop Hypertension) found that eating 9 servings of fruits and vegetables a day would lower blood pressure.  Nine servings can be easily consumed if you have a piece of fruit at breakfast and lunch; then 2 servings of vegetables lunch (for example 2 cups of salad) and then 2 to 3 servings of vegetables at dinner. You can eat fresh, canned or frozen vegetables and fruits.  Canned fruit should be packed in juice or water; canned vegetables that are either low salt or salt free are healthier but if you buy ones with salt in the water you can drain them or rinse the vegetables off.

The health benefits of the Mediterranean diet were initially realized by studying people who ate this diet for generations. The diet is plant-based and includes daily generous servings of extra virgin olive oil at multiple meals. It is clearly not a low-fat diet. Health officials in the US acknowledged the health benefits of a Mediterranean diet decades ago, including the health benefits of extra virgin olive oil. I remember reading editorials in the 1980’s that discussed the health benefits of extra virgin olive oil, but the editorials mistakenly concluded that Americans do not want oil that has a taste so it was thought that Americans would not embrace extra virgin olive oil. Health officials in the US also mistakenly concluded that the health benefits of extra virgin olive oil were due to the high monounsaturated fat content. Hence the development of canola oil, made from the rapeseed plant with the name “canola” coming from the trademark name of the “Rapeseed Association of Canada”. Canola oil has minimal taste and it is reasonably high in monounsaturated fat (62%), but not as high as olive oil (77%).

The idea that the monounsaturated fat content is responsible for the health benefits lead to the development of the Med diet score. (1) The Med diet score gives points to foods of a traditional Mediterranean diet that have been shown to have health benefits like vegetables, fruits, legumes, nuts, and cereals and subtracts points for foods that are unhealthy, like meat and meat products and dairy. Interestingly, for examining the impact of dietary fat, the Med diet score uses the ratio of monounsaturated fat (MFA) to saturated fat (SFA) in the diet being examined, not the extra virgin olive oil content of the diet. If the populations that are being studied are in one of the Mediterranean countries, the MFA: SFA would likely be assessing at least some extra virgin olive oil. However, when the Med diet score is used to assess health, especially outside Mediterranean countries, the data should be examined with caution as you would need to know what foods are supplying the monounsaturated fat. For example in the US, the major source of monounsaturated fat until about 2004 was meat. (2) In 2005 “salad cooking oils” caught up with meat, supplying 23.9 % of the monounsaturated fat in the US diet to 21.4% from meat. While olive oil consumption has increased in the US, in 2005 soybean oil represented close to 80 % of the salad oils consumed in the US. (3) Since that time the soybean oil contribution has decreased with increases mainly in canola and palm oil. (3) However, in 2010 (the last year data is available from the USDA) meat still supplied 21.5% of the monounsaturated fats content of the US diet to 32.3% from salad cooking oils. So a study using the Med diet score to assess health in the US likely has a better chance of finding no benefit, and possibly harm, due to a large proportion of the food source of mono-unsaturated fat could be meat or canola oil.

It is important to note the health and taste attributes of extra virgin olive oil are largely due to the bio-active plant compounds it contains, including phenols. Other grades of olive oil, including “olive oil” and “refined olive oil” undergo refining processes that remove most of the phenols. While the MFA content remains essentially the same, the number of bioactive compounds and phenols are mostly lost. Extra virgin olive oil has been related to decreasing the risk of a range of chronic diseases and improv-ing numerous risk factors for chronic diseases. Extra virgin olive oil has been shown to improve blood pressure (4-6) insulin sensitivity, (7) blood levels of glucose and insulin, (7-10) levels of HDL (11-16) and HDL
function (17,18) and to decrease oxidation (19,20), including decreasing the oxidation of LDL. (5,11,12,14,16,21,22) No other food has the range and magnitude of the health benefits of extra virgin olive oil. If the health benefits of extra virgin olive oil were due to the monounsaturated fat content, all studies using olive oil would have the same health benefits, and they do not. In addition, canola oil would show health benefits, and it does not. (23) The health benefits of extra virgin olive oil are clearly due to the phenols found in extra virgin olive oil as studies assessing the benefits for varying amounts of total phenols show better benefits with higher phenol content (approximately greater than 200 mg/kg) and no benefit with low (< 50 mg/kg) phenol content, a level that would not qualify as extra virgin. (5,12,14,16,17,21)

The traditional Mediterranean diet included extra virgin olive oil out of necessity – it was the only oil option in the area. The fact that it is delicious and has numerous health benefits is indeed a fortuitous bonus. It is possible to see some health benefits from the Med diet score due to the foods receiving a positive score -vegetables, fruits, nuts, legumes- that could contribute to health. However, if the MFA:SFA value is used to assess the contribution from dietary fat outside of the Mediterranean countries, the results should be interpreted with caution.

1. Trichopoulou A, Kouris-Blazos A, Wahlqvist ML, et al. Diet and overall survival in elderly people. Bmj 1995;311:1457-60.
2. Nutrient Content of the U.S. Food Supply, 1909-2010. 2010. 2019, at Accessed February 16, 2019.
3. Trends in U.S. Edible Oil Consumption and the High Oleic Soybean Oil Opportunity: United Soybean Board; 2017.
4. Ferrara LA, Raimondi AS, d’Episcopo L, Guida L, Dello Russo A, Marotta T. Olive oil and reduced need for antihypertensive medications. Arch Intern Med 2000;160:837-42.
5. Moreno-Luna R, Munoz-Hernandez R, Miranda ML, et al. Olive oil polyphenols decrease blood pressure and improve endothelial function in young women with mild hypertension. Am J Hypertens;25:1299-304.
6. Perona JS, Canizares J, Montero E, Sanchez-Dominguez JM, Catala A, Ruiz-Gutierrez V. Virgin olive oil reduces blood pressure in hypertensive elderly subjects. Clin Nutr 2004;23:1113-21.
7. Ryan M, McInerney D, Owens D, Collins P, Johnson A, Tomkin GH. Diabetes and the Mediterranean diet: a beneficial effect of oleic acid on insulin sensitivity, adipocyte glucose transport and endothelium-dependent vasoreactivity. Qjm 2000;93:85-91.
8. Farnetti S, Malandrino N, Luciani D, Gasbarrini G, Capristo E. Food fried in extra-virgin olive oil improves postprandial insulin response in obese, insulin-resistant women. J Med Food;14:316-21.
9. Loued S, Berrougui H, Componova P, Ikhlef S, Helal O, Khalil A. Extra-virgin olive oil consumption reduces the age-related decrease in HDL and paraoxonase 1 anti-inflammatory activities. Br J Nutr;110:1272-84.
10. Madigan C, Ryan M, Owens D, Collins P, Tomkin GH. Dietary unsaturated fatty acids in type 2 diabetes: higher levels of postprandial lipoprotein on a linoleic acid-rich sunflower oil diet compared with an oleic acid-rich olive oil diet. Diabetes Care 2000;23:1472-7.
11. Cicero AF, Nascetti S, Lopez-Sabater MC, et al. Changes in LDL fatty acid composition as a response to olive oil treatment are inversely related to lipid oxidative damage: The EUROLIVE study. J Am Coll Nutr 2008;27:314-20.
12. Covas MI, Nyyssonen K, Poulsen HE, et al. The effect of polyphenols in olive oil on heart disease risk factors: a randomized trial. Ann Intern Med 2006;145:333-41