Ask Me Anything

with Sigma Nutrition Premium

Ask a question

Vitamin C and Low-Carb diets

A former guest Mike Sweeney RD, had an interesting recent interview on a Keto podcast: The claim is at timestamp 46:20. It was interesting to hear a registered dietitian with such *ahem* different views, but I wanted to focus on one particularly interesting claim which I have dug into myself because I previously heard the same claim within the last year. You can listen above for his exact words but the basic claim is this: "Those on low carb diets require less vitamin C than those on high carb diets. This is because Vitamin C and Glucose have a shared transporter (GLUT#). The more carbohydrate in the diet, the more glucose, the more glucose, the higher the vitamin C requirement as they compete for the same transporter. On low-carb, there is less glucose, thus less competition for the transporter, thus a lower Vitamin C requirement." I have heard that this means the RDA for Vitamin C is "irrelevant" and "doesn't apply" to low carb dieters ..... I see a couple of significant problems: (1) Competition for the transporter would only be relevant if either Vitamin C or Glucose were sufficiently high in those areas where the transporters do their job. I believe in the case of hyperglycaemia, there can be an issue with Vitamin C uptake. But where is the evidence that high carbohydrate diets, of themselves result in sufficiently high levels of glucose to make competition for these transporter an issue that would affect Vitamin C requirements? (2) Why would cell requirements for Vitamin C be lower? Rummaging in "Nutrient Metabolism: Structures, Functions and Genes" (Martin Kohlmeier), carbohydrate metabolism does not seem to require Vitamin C. Maybe he is saying that although cell Vitamin C requirements are the same, because of high glucose levels, more vitamin C is needed to outcompete the glucose and reach the cells? It all sounds pretty sketchy so would love to hear you guys take it apart.

Omega 3 Supplmententation worthwhile?

Is there any evidence that otherwise healthy people should be consuming Omega 3 supplements? It's almost blanketly recommended as a staple for most, but are there any benefits in non clinical dosages?

Do you have a podcast where the current most ideal diet for people look like based on the current understanding of nutrition

Listening to multiple experts, podcast, books etc. I don't know what to eat anymore. There are like pro's and cons for everything. Is there a podcast where the best foods to eat are described. So not just protein/carb/fat, but the actual most benefical foods. etc.

Podcast Prep

What are Danny and Alan’s general process for approaching a podcast? From topic choices, literature review, concluding thoughts before entering the podcast, communication, and skeletal structure etc.

Omega 3 Index Baselines in Studies

In omega 3 supplementation studies it doesn't seem to be common practice to test the omega 3 index as a baseline measurement before supplementation. Why is this? How do we know if supplementation is beneficial if people do/do not have adequate levels? It seems to be intake is measured off food frequency questionnaires which can have issues, so why don't we use this marker as a standard?