Are Ketogenic Diets Nutritionally Adequate?

Sardines and a good source of calcium on a ketogenic diet

I was concerned about inadequate calcium consumption during the design of my ketogenic diet. Many experts believe that inadequate calcium intake causes thin, easily broken bones (osteoporosis). But his may not be true. And high calcium consumption seems to have increased risk of premature death in Swedish women. Furthermore, calcium supplementation almost doubled the risk of having a heart attack, at least in Germans. Yeah, it’s complicated.

From the journal Nutrition:

Objective

A 12-week ketogenic diet was shown to have many beneficial effects in healthy obese adults, but it is not clear if the supply of micronutrients is adequate.

Methods

In 35 adult individuals with BMI above 30, the intakes of minerals and their serum levels were analyzed at baseline and at weeks 4 and 12 of the ketogenic diet intervention. The intake of vitamins and serum antioxidative potential were also investigated.

Results

Throughout the diet the intakes of magnesium, calcium, iron, phosphorus and potassium were below recommended values, but their serum levels always remained within the reference range. Nevertheless, the level of calcium decreased significantly (from 2.52 ± 0.10 mmol/L at baseline to 2.36 ± 0.07 mmol/L at week 12, P < 0.001) which could be due to the omission of legumes and reduced dairy intake or due to the high fat intake alone. The levels of phosphate increased concomitantly. Calcium serum levels were negatively associated with ω-6 but not with ω-3 unsaturated fatty acid intake. The intakes of water-soluble vitamins were also too low. However, the antioxidative potential of serum did not change during intervention.

Conclusion

Careful choice of foods which would provide the necessary micronutrients is of utmost importance when consuming ketogenic diet. In the 12 weeks the decreased intakes did not reflect in serum values, but special attention to calcium should be advised if such diet is recommended through longer periods.

Source: Assessment of micronutrients in a 12-week ketogenic diet in obese adults – ScienceDirect

Steve Parker, M.D.

PS: If you have my Conquer Diabetes and Prediabetes book, you already have my ketogenic diet, plus much more.