Friday, March 11, 2011

Grape seeds got to eat them by the bowl full

Further from yesterday's post about grape seeds I did some digging around. I found that the level of grape seeds you need to eat is really high. For example:

  • When rats were feed a diet, which grape skins and seeds (ie waste from wine industry) made up 10%, they didn't develop liver issues when feed a chemical that causes liver damage. As much as I love grapes, I can't see them making 10% of my diet, yet alone the skin and seeds making 10%. 
  • In other rats that were feed 0.5% of diet at grape seed extract had less stomach tumors like the control rats. I couldn't easily find any statement about the weight of average western food intake. Five fruit/veg servings would be 5 x 250 grams. As fruits and vegetables can be approximated as water. Then protein intake between 50 - 100 grams, then on top of this would be some carbohydrate. So 1.5 kg of food daily would be an approximation on the low side. This would then mean 0.5% of 1.5kg is 7 grams. Quick tablet weight approximation from my bottles of pills, a tablet is about 1 gram. So this is 7 tablets a day, every day.  

Thursday, March 10, 2011

Grape seeds - what do we really know ?

It has been a wonderful grape year. We got the first red and white grapes from our vines. Very yummy! I was sitting in the dappled shade of the peach tree, having a Friday afternoon beer while munching on sweet white grapes. I was reading a nutritional product catalog and noticed that they had in their antioxidant tablets grape seed extract. No surprises, as grape seeds are known to have strong antioxidant capabilities.

But it did get me thinking. Firstly do the seeds I swallow get broken down in digestion to give up their nutrients? Or does this only happen when I bit the seeds? As I try not to bit the seeds, as they taste bitter, then am I getting any value from swallowing them? Should I be spitting them out as whole seeds, then grinding them up for a breakfast smoothly like I do with other nuts? What effect does the type of plant have? Do I have a high antioxidant seeding plant, or a low one? How would one find out?

There are many questions that I have yet to answer. However it does illustrate how little we know about optimal health and diet. The media have told us grape seeds are antioxidants, but nothing more than this. This illustrates my frustration with the "wellness" industry and the media. We get told some general principles but not the specifics required to make a solid change in our lives.

I guess this is the motivation to blog! To help bridge the gap.    

Wednesday, March 9, 2011

Vitamin C - take it after surgery

The problem with some vitamin research is that they don't feed high enough levels of the nutrient to see a difference. For example the current RDI for vitamin C in NZ is 30 - 40 mg / day. Therefore a scientist might design a study which uses 2 -3 times the RDI, being in the range from 60 to 120 mg. If the study shows that vitamin C has no effect, so a paper gets published that vitamin C doesn't have an effect on X. Where X was whatever they were studying. However this might not be true, likely low levels of vitamin C aren't going to show a benefit.

Fortunately this issue wasn't the case with a study looking at increasing vitamin C in parenteral nutrition in postoperative gastrointestinal surgery. Parenteral nutrition is when you are feed via a drip. They found at increasing the dose to 100 mg of vitamin C from the RDI didn't given "normal" values of vitamin C in the urine. However at 500 mg the urine levels were above "normal". Markers of oxidative stress were also reduced in the 500 mg group, but not in the 100 mg.

From this I would conclude that after surgery you need 500 mg of vitamin C to obtain your RDI levels. That is when you body is under significant stress, it needs > 10 times the level of vitamin C just to be normal. I also wonder about other nutrients post sugary.