CKD is more prevalent than diabetes among adults living with obesity. Bariatric surgery is the most effective treatment for obesity. Furthermore, for adults with CKD whose BMI prevents them from being a transplant candidate, bariatric surgery may help. But what is a dietitian to do with nutrition recommendations for these patients?
Well, lets take a look at this article published in Nutrients just last year.
A quick bariatric surgery refresher
Bariatric surgery describes a group of surgeries preformed for weight loss.
There are three types of bariatric surgeries
| Type | Examples |
| Restrictive – decreased stomach size, early satiety with smaller food volumes | Gastric BandVertical-based gastroplastySleeve Gastrectomy |
| Malabsorption – decreased nutrient absorption through excluding or shortening some part of the GI tract | Jejunal-ileal BypassDuodenojejenual bypassBiliopancreatic diversion with or without a duodenal switch |
| Restrictive and Malabsorptive – combines a restriction on stomach size with an exclusion or shortening of some part of the gut | Roux-En-Y Gastric BypassOne Anastomosis Gastric Bypass |
According to these authors, in 2016 the three most common surgeries were Sleeve Gastrectomy, Roux-En-Y and One Anastomosis Gastric Bypass.
Nutrition Recommendations
I have summarized the authors nutrition recommendations in the table below:
| Nutrient | Target | Rationale/Comments |
| Energy | 1200-1800kcal | Based on the Look AHEAD trial, this energy level demonstrated benefit |
| Protein | For pre-dialysis 0.8-1.0g/kg ideal body weight (IBW)For Dialysis >1.2g/kg IBWFor Transplant > 1.1g/kg IBW | Bariatric surgery reduces protein absorption and makes consuming adequate protein more challenging. Patients may require protein supplements or keto-analogues. |
| Phosphate | Maintain normal serum levels | Despite potential changes in the absorption of these nutrients, recommendations suggest adjusting dietary intake to maintain normal serum values. |
| Calcium | ||
| Potassium | ||
| Magnesium | ||
| Iron | Maintenance: 45-60mgDeficiency: at least 200mgCo-administer with 250mg Vitamin C | Bariatric surgery reduces iron absorption and adults are at higher risk of anemia post-operatively. CKD also increases the risk of anemia. Higher doses of oral iron or IV Infusions may be needed to treat deficiencies. |
| Folic Acid | Maintenance: 400ug/day, except in pregnancy or planning to conceive then 800-1000ug/dayDeficiency: 1mg | Recommendation for folic acid follows the same guidance as the general post-bariatric surgery population. Theses recommendations are not specific to those with CKD post bariatric surgery. |
| Vitamin B12 | 350-500ug/day orally or 1mg IM monthly or 3mg IM every 3 months | Recommendation for B12 follows the same guidance as the general post-bariatric surgery population. B12 deficiency may not appear until 3-5 years after surgery. |
| Vitamin D | Maintenance: 3000IU per dayDeficiency: 50000IU 3 times per week of Vitamin D2 or 3000-6000IU daily per day | Active Vitamin D supplementation may be indicated if parathyroid hormone levels raise above normal ranges. Though there are no specific recommendations for active Vitamin D. |
| Vitamin E and K | Meet the DRI | Deficiency of Vitamin E and K is less common after bariatric surgery. |
| Vitamin A | Supplementation should not exceed the DRI | 70% of patients post bariatric surgery develop a Vitamin A deficiency. However CKD tends to be associated with higher Vitamin A levels in the blood. There is potential for toxicity with high Vitamin A supplementation in this population. |
Special Considerations
Fluid: the target fluid intake post-bariatric surgery is >1.5L per day. This recommendation is inline with fluid recommendations for many stages of CKD. However, for those on dialysis, adjust fluid intake to ensure intra-dialytic weight gain is not more than 2-2.5kg.
Dumping Syndrome: Can occur post bariatric surgery. There are no specific recommendations for adults experiencing dumping syndrome and living with CKD. The nutrition goals for management of dumping syndrome are to delay gastric emptying and carbohydrate absorption. The general recommendations to achieve these goals are:
1) Eat 5-6 small meals per day
2) Keep total food volume per meal to ~150mL
3) Eat slowly in a calm environment
4) Avoid drinking and eating at the same time
5) Drink fluids slowly up to 30 minutes before a meal and 30-60 minutes after meals
6) Limit easily digestible carbohydrates such as glucose, fructose and sucrose or high glycemic index foods.
7) Have a combination of carbohydrates, protein and fat with each meal
8) Consider adding guar gum, pectin or glucomannan to slow gastric emptying.
Take Aways
I have already had a few patients in my practice that are living with kidney disease after bariatric surgery and odds are I will have a few more. I am glad I found this 2023, but acknowledge that some some of the recommendations remain vague. As this population grows, I anticipate we will continue to learn more. One of my favourite things to say to patients is the “the only promise I will make is that things change.” and I think this is a population where that promise is a good one to make.
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