In the news: Vitamin K Linked to Cataract Risk; Best Time to Take Probiotics?

Can Vitamin K Intake Influence Cataract Risk?

The answer to that question is not yet known, but a new observational study has linked higher intake of vitamin K1 with a lower risk of cataract (1).

While the underlying processes of cataract formation are still unclear, growing evidence suggests a potential role of oxidative stress and inflammation.

Vitamin K1 is best known for its role in blood clotting and bone metabolism. However, it may also play a role keeping calcium from accumulating in artery walls and has been shown to have anti-inflammatory activity.

To investigate whether vitamin K1 could potentially play a protective role in the eye’s lens, researchers looked at the diets of 5,860 older individuals who took part in the Prevención con Dieta Mediter-ránea clinical trial or PERIMED Study and the development of cataracts among the participants.

After a follow–up of nearly 6 years, a total of 768 new cataracts were documented. The highest dietary intake of vitamin K1 was associated with a 29% lower risk of cataract compared to the lowest intake of the vitamin.

This is the first time vitamin K1 has been linked to cataract risk in humans, so further research is required to validate this observation. However, the role of vitamin K1 does appear to be expanding, so keep eating good sources of this vitamin: green leafy vegetables such as lettuce, broccoli, kale, Swiss chard, parsley and spinach.

Is There a “Best” Time to Take Probiotics?

Probiotics are healthful bacteria that are either the same as or very similar to bacteria that normally colonize the human body. These bacteria form diverse, complex and large communities– their numbers in the digestive tract alone surpass the number of total cells in the body.

Probiotics research has exploded over the last few years, with studies looking at the potential effects of specific bacterial species and strains on various health parameters such as digestion, immunity and mood.

Use of supplemental probiotics is on the rise as well, leading to the common question: When should they be taken to better the odds of surviving passage through the stomach?

Bacteria are vulnerable to stomach acidity. Taking them without having eaten would mean a shorter stay in the stomach, but with a higher level of acidity. Taking them with a meal results in the bacteria staying in the stomach longer, though stomach acidity gradually decreases with the addition of food.

The results of a new and preliminary study (2) suggest that the timing of probiotic consumption is not that important. In the study, healthy participants were randomly assigned to take a probiotic supplement 30 minutes before or 30 minutes after breakfast. (The probiotic consisted of 4 billion colony forming units or CFUs of Bifidobacteria longum species BB536 strain combined with 1 billion CFUs of Lactobacillus rhamnosus species HN001 strain).

At the end of one month, the difference in timing did not appear to influence the number of participants with detectable levels of the bacterial strains consumed– both groups had an increase in bacterial load. The groups also displayed a beneficial change in the composition of intestinal bacteria. The probiotic was associated with reductions in bacterial families that have been linked to obesity or to the risk of developing inflammatory bowel disease.

More and larger studies that examine the best timing for probiotic consumption are warranted to confirm these findings.

References

1. Camacho-Barcia ML, et al. Association of Dietary Vitamin K1 Intake With the Incidence of Cataract Surgery in an Adult Mediterranean Population: A Secondary Analysis of a Randomized Clinical Trial. JAMA Ophthalmol. 135:657-61, 2017.
2. Toscano M, et al. Effect of Lactobacillus rhamnosus HN001 and Bifidobacterium longum BB536 on the healthy gut microbiota composition at phyla and species level: A preliminary study. World J Gastroenterol. 23: 2696–704, 2017.