This study, published recently in the BMJ and reviewed in the NY Times, definitely caught my attention.  The study links the consumption of potatoes to high blood pressure and I have quite a few thoughts about it. Here are my take home points:

• Potatoes are often recommended in the “DASH” diet (Dietary Approaches to Stop Hypertension) because they are high in potassium, low in sodium and fat, and depending on the type, a good source of fiber.

• However, there have been concerns about the glycemic index of potatoes and how that might have a negative impact on cardiovascular health.

•  The researchers of this study wanted to determine whether a higher intake of baked or boiled potatoes, french fries, or potato chips is associated with higher incidence of hypertension.

•  To answer this, more than 180,000 women and men from 3 large U.S. health studies were followed for over 25 years The participants of the study self reported how often they ate potatoes AND also self reported whether they had been diagnosed with hypertension by a health professional.

• The study found that  after controlling for physical activity, weight, and a few other factors, more potato consumption was associated with hypertension.

• Specifically, having 4-6 baked or boiled potatoes  a week increased the risk of hypertension by 11% compared to having 1 potato once a month.  The result was unsurprisingly worse with french fries. Four or more 4 oz servings of French fries a week increased the risk by 17 %. Strangely, consumption of potato chips was not associated with any increased risk.

• The researchers also found that replacing one serving a day of of boiled, baked or mashed potatoes with one serving of non-starchy vegetables was associated with a lower risk of developing hypertension.

• There are some important limitations of this study that should give one pause before giving up potatoes, especially if you enjoy them, feel great on them, and you are healthy without high blood pressure.

These limitations include the following:

1. Because this type of study was observational, it CANNOT establish a cause and effect relationship between potatoes and high blood pressure. However, reading a title in the NY Times that states “Potatoes Tied to High Blood Pressure Risk” can be alarming to those who don’t realize this.

2. The frequency with which the study participants ate potatoes was not objectively measured, but only self-reported. In other words, the participants reported how much potatoes they’d eaten during a certain time period, which may mean less accuracy of this data.

3. The participants’ blood pressures were also not measured during the study.The participants simply reported whether or not they had been diagnosed with high blood pressure by a health professional. Therefore, there may have been more cases of elevated blood pressure in EITHER group, and it is hard to conjecture which group would have more under-reported cases.

4. The glycemic index of a potato varies depending on the type of potato and the method in which it is cooked; this was not fully addressed in the study.

5. One detail of this study that I think is a glaring issue, is that there was no analysis of what was eaten with the potato. Digestion and efficient assimilation of the carbohydrates/sugars in a food can be extremely affected by what other foods it is combined with. For example, a baked potato with steamed kale may result in a very different glycemic and/or BP response than baked potato with sour cream and a side of steak.