A friend recently shared this tweet with me:
She had asked the tweeter for more details but hadn’t received a response. My response: “Ugh. No wonder so many people don’t trust us as dietitians”.
Of course, it’s Florida orange juice that imparts these benefits. Because oranges from other locales couldn’t possibly impart the same benefits (<— please note this should be written in the yet to be developed sarcasm font). Even so, is the benefit even all that meaningful? I’d argue no.
While I can’t be certain that the study I found is the one the tweeter was referring to it was the top hit and was sponsored by Tropicana orange juice so it fits the bill. The study looked at a very small group of individuals with elevated cholesterol. There were only 25 participants, 16 healthy men, and 9 post-menopausal women. This means that the results cannot be extended to apply to pre-menopausal women or “unhealthy” individuals. There were additional strict criteria that participants had to meet: 1. have initial fasting plasma triacylglycerol (blood lipid) concentrations in the normal range, 2. be habitual or occasional orange juice drinkers, 3. be free of thyroid disorders, kidney disease, and diabetes, 4. have an alcohol intake of ≤2 drinks/d, 5. not be receiving hormone replacement therapy if female. With such a small sample size of people meeting such precise criteria, no concrete conclusions can be drawn from this study.
However, the researchers still drew conclusions. Namely that three cups of orange juice a day can lower LDL and increase HDL blood levels. They found that HDL levels were increased by 21% and the HDL-LDL ratio was decreased by 16%. That sounds fairly impressive but is it really? Well, no, not really. The average HDL level increased from 1.0 to 1.3. Anything over 1.0 is good anyway so they weren’t all that badly off to begin with. The HDL-LDL ratio really only changed because of the increase in HDL as LDL levels went from an average of 3.6 to 3.5. Not a significant change.
What the study doesn’t tell you is that cholesterol recommendations are only made in relation to risk of cardiovascular disease. If your risk level is low then an LDL of under 5.0 is fine. If your risk is high then an LDL of less than 2.0 is ideal. Risk level is determined by family and medical history. None of these factors were discussed in the current study despite the fact that the cholesterol levels measured are essentially meaningless without being placed in the context of CVD risk.
Can we just go back to that THREE cups of OJ a day again? The researchers found no significant change in cholesterol levels at one or two cups of OJ a day. Only at three cups a day. That’s a considerable amount of orange juice. Considering that a serving size of juice is 1/2 cup and most dietitians recommend no more than one serving per day I find it hard to fathom recommending 6 servings of juice every day for a slight increase in HDL levels. The researchers note that as OJ increased fibre intake decreased. They didn’t mention any other aspects of diet. There was no comparison to consumption of whole oranges, other fruit or vegetable juices, or any other dietary changes. Based on this study alone I would absolutely not advise anyone wishing to improve their blood cholesterol levels to drink 63 grams (more than 15 teaspoons) of liquid sugar daily.