Would you pay for a bottle of juice? This may sound crazy but many people will pay a pretty penny for a bottle of juice if it promises things like ‘longevity’ and ‘cancer-free living’. These fruit juices have taken the health food market by storm. In fact, there are so many of them on the market now, keeping them straight can be a little confusing. Many of these juices make claims that are not backed by any really good evidence. For this reason, most of these juice manufacturers rely on testimonials from people who claim the juice has helped or cured an ailment they had.
Read on to figure out how to sort through these fancy fruits:
Mangosteen is an Asian fruit. The juice it makes is marketed under names such as XanGo, Mangoxan and Thai-Go. Most of these brands contain mangosteen juice mixed with other juices. The producers of this juice claim that this juice is an extraordinary antioxidant. This antioxidant effect may be contributed to the xanthones found in the juice. Xanthones are compounds that have antioxidant properties.2 It has also been purported to strengthen the immune system, support good respiratory health and aid joint function. It also claims to contribute to a healthy intestinal tract.1 The juice’s possible benefits in the GI tract are thought to be due the tannins present in the juice. Tannins are thought to have a sort of astringent affect on the intestinal walls, which may help reduce diarrhea.2 Although the manufacturers make some great claims, there is no real evidence available that show that this juice benefits any specific health condition. There are currently no known drug interactions or side effects documented for mangosteen. This of course does not mean there aren’t any. It only means that none have been documented yet.
Acai, pronounced ah-sah-yee, is a fruit that grows in South America. The juice is marketed under such product names as MonaVie, Sambazon and Bossa Nova. The producer of this juice claims that this juice has a low glycemic index (meaning it does not contain many pure sugars that will spike your blood sugar) and that there is no other fruit available that has as much antioxidant power.3 There has been some evidence that shows that acai juice may have activity against leukemia cells, however, there is no good evidence that this juice is good for any other disease or condition.
Pomegranate juice is available as a pure juice or mixed with other juices. Pom Wonderful, a popular brand of this juice, claims that this juice is full of antioxidants and may help with such conditions as cancer, heart health and may have anti-aging properties. Unlike many other health supplements on the market, there are some preliminary studies on pomegranate juice that show promising results with regard to these claims. For examples, some data suggests that this juice may slow the progression of atherosclerosis (hardening of the arteries). It is thought that pomegranate juice helps accomplish this by preventing the formation of plaques that can cause arteries to clog. It is also thought that it helps dilate the blood vessels. Because of its effects on blood vessels, it has been thought that pomegranate juice might also prevent erectile dysfunction.
It is also thought that pomegranate juice may help reduce cholesterol by reducing the body’s ability to make cholesterol in the liver. Pomegranate juice has also been shown to reduce blood pressure by reducing the activity of an enzyme called ACE in the body.
Finally, there may be evidence from animal studies that pomegranate juice inhibits the growth of cancer cells in prostate and breast cancer.
Many of the potential benefits of pomegranate juice are thought to be due to its high polyphenol content. Polyphenols are antioxidants. Pomegranate juice is thought to have as much as three times the polyphenol content of red wine, blueberries or green tea.
Drug interactions and side effects for pomegranate juice are not all known, however, people who take blood pressure medications should use caution when drinking pomegranate juice or eating the fruit. Although not well documented, taking blood pressure medications with this juice may cause extremely low blood pressure which can lead to fainting, heart problems or worse. It also appears that pomegranate juices inhibit many of the same enzymes in the system that grapefruit juice does. This means that you should check with your doctor or pharmacist before drinking these juices with certain other medications, such as those that use the CYP2D6 and CYP3A4 enzymes in the body. Drinking the juice with these medications may cause levels of the medication to change in the body. This juice has also been shown to cause allergic reactions, even in people who have taken it for many years. 2 It is important if you experience any symptoms of a serious reaction such as a rash or swelling of the tongue or throat, that you stop eating/drinking the pomegranate and seek medical attention immediately.
This plant with beautiful red berries grows in China. It has many other names such as Chinese Boxthorn, Chinese Wolfberry, Di Gu Pi, Gou Qi, Ning Xia Gou Qi and Barberry Matrimony Vine. It is usually mixed with other juices. The manufacturer of this juice claims that this juice promotes longevity and may help lower cholesterol in the body. Goji also contains many nutrients like beta-carotene, niacin, vitamin B6 and vitamin C. Despite these claims and the fact that it contains these nutrients, there is no compelling evidence that Goji helps with any particular condition.
As for side effects, few are reported. It is recommended that pregnant women do not consume Goji as it has been shown to have mild uterine stimulant properties. Goji may cause some drug interactions with those drugs that use the CYP2C9 enzyme in the body (ask your doctor of pharmacist if you are taking any of these medications). Patients taking warfarin (Coumadin®) should be especially careful.
Some products like Thai-Go combine sea buckthorn with other juices. Weleda is an example of a brand that markets pure sea buckthorn juice. These juices contain many nutrients like beta-carotene, vitamins A, B1, B2, B6, C and E.2 It is also thought to contain beneficial fatty oils. It is said that sea buckthorn can lower cholesterol, help heal gastric ulcers, reduce cancer cell growth, promote wound healing and help prevent blood clots.2,4 These all sound well and good, however, there is no real evidence that sea buckthorn can accomplish any of these claims. There are no reports of serious side effects from sea buckthorn.
This is often referred to as ‘Noni Juice’. The manufacturers claim that this juice can boost the immune system, increase energy and act as an antioxidant.5 There is preliminary data from animal studies that this substance may be useful in the future for treating conditions like cancer, HIV, pain, and infections.2 This does not mean that it is safe and/or effective in humans, however. In fact there is no reliable data in humans as of yet to show that Noni is effective for any human condition. One should also be cautious in that there have been cases of possible liver damage from the use of Noni. One patient even required a liver transplant.2 Patients who take acetaminophen (Tylenol®) should be especially careful. Noni also contains high levels of potassium. For this reason patients who take medications that can increase potassium levels should be careful as well as too much potassium in the body can cause serious side effects like heart arrhythmias (check with your doctor or pharmacist). Patient with kidney problems should also be careful as these patients are prone to having higher blood potassium levels anyway. As with any other supplement that has unknown effects, pregnant women should not drink Noni juice.
The Bottom Line
Most of these juices do not have any compelling evidence that show that they do what they claim. Most of the claims put forth by these manufacturers are backed not by studies, but by testimonials of people who have used them that claim extraordinary results. All in all, most of these juices (with the exception of Noni) do not appear to have any harmful side effects so consuming them will probably not hurt, however, it is important to remember juices can be high in calories and that consuming too much of any juice can thwart weight loss or weight maintenance plans if one is not careful. Unknown drug interactions is also a potential problem with these juices. Pregnant women should avoid these juices as side effects for these substances has not been clearly established.
1. XanGo juice. www.xango.com/learn/. (Accessed January 2, 2007).
2. Jellin JM, Gregory PJ, Batz F, et al. Pharmacist's Letter/Prescriber's Letter Natural Medicines Comprehensive Database. http://www.naturaldatabase.com. (Accessed January 2, 2007).
3. Bossa Nova acai juice. www.bossausa.com/home_bossa_ove_acai_juice.html (access January 2, 2007).
4. Li T. Product development of sea buckthorn. In: Janick J, Whipkey A, Eds. Trends in new crops and new uses. Alexandria, VA: ASHS Press, 2002:393-8.
5. Tahitian Noni Juice. www.tahitiannoni.com/united_states/english/retail/index.html?r=399. (Accessed January 2, 2007).