I was curious about how much fat exactly we need at a meal when taking the fat soluble vitamins D and K so I looked it up. I wanted to share here in case it is helpful to anyone.
Research suggests that 11g of fat at a meal is what is needed for optimal absorption of these vitamins. Some research suggested that higher fat meals don't yield the same increased absorption but more recent research suggests that this is not the case if the source are are healthy fats such as olive oil - in this case 30g of fat led to a 32% higher absorption level.
I also read that as our body's store these vitamins, it also depends on how much body fat we have.
This provides a summary of the research that has been carried out in this area. Unfortunately the papers I came across are behind a paywall: rawnutrients.co.nz/blogs/he...
Written by
Houseelf
To view profiles and participate in discussions please or .
"The fat-soluble vitamins (A, D, E, and K) are likely to be better-absorbed if taken with a meal that contains fats. In fact, one study found that taking vitamin D with dinner rather than breakfast increased blood levels of vitamin D by about 50%. If you take a fish oil supplement along with fat-soluble vitamins, this may help a little, but not by much -- the amount of fat in a fish oil capsule is only about 1 gram, while studies that have shown increased absorption of fat-soluble vitamins with meals containing about 15 grams or more. " consumerlab.com/answers/whi....
"It may be best to take fat-soluble vitamins apart from one another, as evidence (mainly from animal and cell studies) suggests that moderate to large doses of fat-soluble vitamins reduce absorption of other fat-soluble vitamins - by about 10 to 50% - due to competition. Absorption of vitamin K appears to be particularly reduced by other fat-soluble vitamins, while vitamin A absorption is least affected and may actually be better absorbed when taken with vitamin E (Goncalves, Food Chem 2015). Taking vitamins D, E, or K several hours before or after other fat-soluble vitamins would seem to maximize their absorption."
Thank you for adding to this @urs2022. I think I will continue to take my vitamin D and K at the same time however as for osteoporosis they are taken together with calcium for optimal effect.
There are lots of good, interesting answers here, and I'm not sure I can add anything. I don't even know if this anecdote pertains to the discussion at hand, but after reading I should take Vit D with fat, I started taking it with a tsp or so of cod liver oil.
Mind you, I had been taking 10,000, then 5000 iu of Vit D daily since the start of covid. When my D level was tested in March if 2023, it was 44. (No idea what it had been before then.) Perhaps around...May, (my bone health journey started in January 2023, and my practice, if you will, is still evolving,) I added the cid liver oil.
Saw an endocrinologist for the first time in August 2023, and he repeated the test for D because he couldn't find it in the records I brought him. My level had gone up to 117!
I did reduce my intake to 2000 iu per dr's instructions, and quit taking it with cod liver oil; dr retested in October, and it was down to 77.
Again, I don't know if this is even pertinent, but it seems to me that a tsp of cod liver oil taken at the same time absolutely enhanced absorption.
Also for what it's worth, this January I had my first post-diagnosis DEXA. In one year, my t-scores in my hips had improved about 4%, and in my spine, 14.6%. I did take 9-10 doses of Fosamax, 3 doses in late spring, the remainder in late fall. Otherwise, the only interventions I made were "natural", including several new supplements (boron, Vit K2, cod liver oil, magnesium glycinate over the citrate I'd been taking,) and worked to improve gut health generally. I'd already been walking and working to build strength insofar as my wonky back would allow it, and I started using a vibration plate 3xs/week for 30 minutes at the beginning, then dropped to 20 minutes because I can't figure out what I really should do. My osteoporosis is severe, it's still severe, but a 14.6% improvement in my spine in barely a year, to me, is fantastic! Who knows, maybe better Vit D absorption played a role.
Thank you for adding your story to this josephinius1 and yes, your most recent results are fantastic! It's important to find the positives where we can. I absolutely believe the combination of fat with vitamin D made a difference to your vitamin D level as vitamin D is a fat soluble vitamin and needs fat for it to be absorbed. The research I shared was more be being the way I am and wondering whether there was an optimal amount!
I started taking vitamin D during the pandemic as well as it was tested for the first time then and I was advised to take some. I took it with fat then but increased my vitamin D in 2023 (I -doubled it to 2000iu) and started taking it at the same time as M7-K2 (from natto). This is the only change I made from my previous scan before the most recent scan at the end of last year. I don't like to tempt fate so to speak, but there has been a slight improvement in spine, neck and a great improvement in my hips. I have been doing daily walks, yoga and focused on nutrition for many years, the 2000iu vitamin D+M7-K2 is the only real change I made. It helped bring my parathryoid down which will have played a major role.
That's awesome! Makes me feel that much more encouraged that more things will yield more results! Next up for me is to start getting stronger, for real. PT says I'm not strong enough to seriously lift (yet) and I should probably listen to her, but how do you get strong without starting where you are and working your way up? True for everything, right?
Content on HealthUnlocked does not replace the relationship between you and doctors or other healthcare professionals nor the advice you receive from them.
Never delay seeking advice or dialling emergency services because of something that you have read on HealthUnlocked.
Fear of too many vitamins.
Osteoporosis and HRT for the over 60s
Vitamin K advice 
To take or not to take!!
