Certain supplement combinations could pose a risk to consumer health, experts warn

Experts from Ben's Natural Health have put together a guide depicting nutraceutical and pharmaceutical combinations that can negatively impact cosumer health. 

According to the company, combining supplements can be highly beneficial in supporting health, but some combinations can reduce a functional ingredient's efficacy or even cause health problems in prolonged use.

With around 77% of those living in the US using dietary supplements, it is important to inform them of 'bad' combinations, and how they might impact their health.

Backed by clinical research, Ben's Natural Health has identified nine supplement/therapeutic combinations that should be avoided:

• Calcium and iron: Calcium intake can inhibit iron absorption by up to 50%, which could significantly impact those with anaemia. To mitigate these effects, iron supplements should be taken on an empty stomach alongside vitamin C to encourage absorption, and should be taken independently of calcium with at least two hours in between.¹
   
• Vitamin E and omega-3s: Vitamin E and omega-3s can both act as blood thinners, meaning they can increase a user's bleeding risk when taken together. This combination is not recommended for those on anticoagulant therapies, and high doses of this combination should be avoided.²
   
• St. John's wort and SSRIs: As St. John's Wort increases serotonin levels naturally, it can be dangerous to combine it with selective serotonin reuptake inhibitors (SSRIs), as this can lead to serotonin syndrome. Studies have found that those taking St. John's wort alongside SSRIs had a 25% higher risk of developing serotonin syndrome.³
   
• Vitamin K and blood thinners: Vitamin K is involved in the blood clotting process, so taking the nutraceutical alongside blood thinners can reduce their efficacy. Vitamin K intake has been proven to increase the risk of complications in patients on anticoagulant therapies by 20%; Therefore, high doses of the vitamin should be avoided.⁴
   
• Calcium and magnesium (high doses): Calcium and magnesium taken at high doses simultaneously can put strain on the kidneys and boost a user's risk of developing kidney stones, with studies seeing a 15% increase in the risk of kidney stones when combining the minerals. Experts therefore recommend that individuals take these supplements at differing times.⁵
   
• Zinc and copper: High zinc intake inhibits copper absorption, potentially leading to deficiency and other symptoms such as anaemia and immune suppression. Those taking more than 40mg of zinc per day are 25% more likely to experience copper deficiency. Consumers should therefore focus on balancing their intake of these two minerals.⁶
   
• Melatonin and other natural sleep aids: Melatonin usage, when combined with other sedating nutraceuticals, can cause significant daytime drowsiness — potentially increasing a user's risk of accidents. By combining such combinations, reaction times can be notably affected.⁷
   
• Vitamin D and calcium in high doses: When taken simultaneously, high-dose vitamin D and calcium can increase an individual's risk of developing hypercalcaemia, which can result in arterial calcification and kidney stones. This combination has been linked to a 30% increase in kidney issues within users.⁸
   
• Vitamin B12 and vitamin C: Taking high doses of vitamin C can cause the degradation of vitamin B12 before its absorption. 500mg or more has been shown to reduce B12 absorption, which can result in fatigue and anaemia. Therefore, experts recommend that vitamin C is taken earlier in the day, followed by B12 a few hours later.⁹

References

1  Rombouts EK, Rosendaal FR, van der Meer FJ. "Daily vitamin K supplementation improves anticoagulant stability." Circulation. 2007;116(7):737-742. 
2  Hallberg L, Brune M, Rossander-Hulthén L. "Is there a physiological role of vitamin C in iron absorption?" Ann N Y Acad Sci. 1987;498:324-332. 
3  Harris WS, Mozaffarian D, Rimm E, et al. "Omega-6 fatty acids and risk for cardiovascular disease: a science advisory from the American Heart Association Nutrition Subcommittee of the Council on Nutrition, Physical Activity, and Metabolism." Circulation. 2009;119(6):902-907. 
4  Lantz MS, Buchalter E, Giambanco V. "St. John's Wort and antidepressant drug interactions in the elderly." J Geriatr Psychiatry Neurol. 1999;12(1):7-10. 
5  Taylor EN, Curhan GC. "Dietary calcium from dairy and nondairy sources, and risk of symptomatic kidney stones." J Urol. 2003;169(4):986-992. 
6  Sandström B. "Micronutrient interactions: effects on absorption and bioavailability." Br J Nutr. 2001;85(S2). Link to study
7  Attenburrow MJ, Dowling BA, Sargent PA. "Effect of melatonin on subjective ratings of sleep and mood in seasonal affective disorder." J 8 Affect Disord. 1999;56(1):41-46. 
8  Aloia JF, Chen DG, Yeh JK, et al. "Calcium and vitamin D supplementation in postmenopausal women." Am J Med. 2005;118(11):1228-1233. 
9  Russell RM, Suter PM. "Vitamin requirements of elderly people: an update." Am J Clin Nutr. 1993;58(1):4-14.